diff --git a/mvn-defaults/pom.xml b/mvn-defaults/pom.xml
index e7685b19d..4299d76d7 100644
--- a/mvn-defaults/pom.xml
+++ b/mvn-defaults/pom.xml
@@ -639,6 +639,7 @@
                     </execution>
                 </executions>
                 <configuration>
+                    <argLine>--enable-preview @{argLine}</argLine>
                     <forkCount>1</forkCount>
                     <reuseForks>false</reuseForks>
                     <includes>
@@ -903,6 +904,7 @@
                         <groupId>org.apache.maven.plugins</groupId>
                         <artifactId>maven-javadoc-plugin</artifactId>
                         <configuration>
+                            <additionalJOptions>--enable-preview</additionalJOptions>
                             <release>21</release>
                             <doctitle>${javadoc.name}</doctitle>
                             <windowtitle>${javadoc.name}</windowtitle>
@@ -911,6 +913,7 @@
                             <detectOfflineLinks>false</detectOfflineLinks>
                             <!--                    <additionalparam>-Xdoclint:none</additionalparam>-->
                             <additionalOptions>
+
                                 <additionalOption>-Xdoclint:none</additionalOption>
                             </additionalOptions>
                             <!--                    <additionalJOption>-Xdoclint:none</additionalJOption>-->
diff --git a/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/HttpDriverAdapter.java b/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/HttpDriverAdapter.java
index b443117fa..6da85376e 100644
--- a/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/HttpDriverAdapter.java
+++ b/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/HttpDriverAdapter.java
@@ -16,16 +16,16 @@
 
 package io.nosqlbench.adapter.http;
 
-import io.nosqlbench.adapter.http.core.HttpFormatParser;
-import io.nosqlbench.adapter.http.core.HttpOp;
-import io.nosqlbench.adapter.http.core.HttpOpMapper;
-import io.nosqlbench.adapter.http.core.HttpSpace;
+import io.nosqlbench.adapter.http.core.*;
+import io.nosqlbench.nb.api.components.core.NBComponentProps;
 import io.nosqlbench.nb.api.config.standard.ConfigModel;
 import io.nosqlbench.nb.api.config.standard.Param;
 import io.nosqlbench.adapters.api.activityimpl.OpMapper;
 import io.nosqlbench.adapters.api.activityimpl.uniform.BaseDriverAdapter;
 import io.nosqlbench.adapters.api.activityimpl.uniform.DriverAdapter;
 import io.nosqlbench.adapters.api.activityimpl.uniform.DriverSpaceCache;
+import io.nosqlbench.nb.api.engine.metrics.instruments.MetricCategory;
+import io.nosqlbench.nb.api.engine.metrics.instruments.NBMetricHistogram;
 import io.nosqlbench.nb.api.labels.NBLabels;
 import io.nosqlbench.nb.api.components.core.NBComponent;
 import io.nosqlbench.nb.annotations.Service;
@@ -41,8 +41,16 @@ import java.util.function.Function;
 @Service(value = DriverAdapter.class, selector = "http")
 public class HttpDriverAdapter extends BaseDriverAdapter<HttpOp, HttpSpace> {
 
+    public final NBMetricHistogram statusCodeHistogram;
+
     public HttpDriverAdapter(NBComponent parent, NBLabels labels) {
         super(parent, labels);
+        this.statusCodeHistogram = create().histogram(
+            "statuscode",
+            Integer.parseInt(getComponentProp(NBComponentProps.HDRDIGITS).orElse("3")),
+            MetricCategory.Payload,
+            "A histogram of status codes received by the HTTP client"
+        );
     }
 
     @Override
@@ -54,7 +62,7 @@ public class HttpDriverAdapter extends BaseDriverAdapter<HttpOp, HttpSpace> {
 
     @Override
     public Function<String, ? extends HttpSpace> getSpaceInitializer(NBConfiguration cfg) {
-        return spaceName -> new HttpSpace(getParent(), spaceName, cfg);
+        return spaceName -> new HttpSpace(this, spaceName, cfg);
     }
 
     @Override
@@ -83,5 +91,4 @@ public class HttpDriverAdapter extends BaseDriverAdapter<HttpOp, HttpSpace> {
 
         return super.getConfigModel().add(HttpSpace.getConfigModel()).add(thisCfgModel);
     }
-
 }
diff --git a/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/core/HttpMetrics.java b/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/core/HttpMetrics.java
deleted file mode 100644
index 8cd4a301a..000000000
--- a/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/core/HttpMetrics.java
+++ /dev/null
@@ -1,49 +0,0 @@
-/*
- * Copyright (c) 2022-2023 nosqlbench
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package io.nosqlbench.adapter.http.core;
-
-import com.codahale.metrics.Histogram;
-import io.nosqlbench.nb.api.engine.metrics.instruments.MetricCategory;
-import io.nosqlbench.nb.api.labels.NBLabeledElement;
-import io.nosqlbench.nb.api.labels.NBLabels;
-import io.nosqlbench.nb.api.components.core.NBComponent;
-
-public class HttpMetrics implements NBLabeledElement {
-    private final NBComponent parent;
-    private final HttpSpace space;
-    final Histogram statusCodeHistogram;
-
-    public HttpMetrics(NBComponent parent, HttpSpace space) {
-        this.parent = parent;
-        this.space = space;
-        statusCodeHistogram = parent.create().histogram(
-            "statuscode",
-            space.getHdrDigits(),
-            MetricCategory.Payload,
-            "A histogram of status codes received by the HTTP client"
-        );
-    }
-
-    public String getName() {
-        return "http"+("default".equals(this.space.getSpaceName())?"": '-' + space.getSpaceName());
-    }
-
-    @Override
-    public NBLabels getLabels() {
-        return space.getLabels();
-    }
-}
diff --git a/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/core/HttpOp.java b/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/core/HttpOp.java
index de1726237..9eb871ab4 100644
--- a/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/core/HttpOp.java
+++ b/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/core/HttpOp.java
@@ -19,24 +19,13 @@ package io.nosqlbench.adapter.http.core;
 import io.nosqlbench.adapter.http.errors.InvalidResponseBodyException;
 import io.nosqlbench.adapter.http.errors.InvalidStatusCodeException;
 import io.nosqlbench.adapters.api.activityimpl.uniform.flowtypes.CycleOp;
-import io.nosqlbench.adapters.api.activityimpl.uniform.flowtypes.RunnableOp;
-import org.apache.logging.log4j.core.tools.picocli.CommandLine;
-import com.google.gson.JsonArray;
-import com.google.gson.JsonElement;
-import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
-
-
 import java.net.http.HttpClient;
 import java.net.http.HttpRequest;
 import java.net.http.HttpResponse;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Spliterators;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.regex.Pattern;
-import java.util.stream.StreamSupport;
 
 public class HttpOp implements CycleOp {
 
@@ -75,7 +64,7 @@ public class HttpOp implements CycleOp {
         try {
             CompletableFuture<HttpResponse<String>> responseFuture = client.sendAsync(request, bodyreader);
             response = responseFuture.get(space.getTimeoutMillis(), TimeUnit.MILLISECONDS);
-            space.getHttpMetrics().statusCodeHistogram.update(response.statusCode());
+            space.statusCodeHistogram.update(response.statusCode());
 
             if (ok_status != null) {
                 if (!ok_status.matcher(String.valueOf(response.statusCode())).matches()) {
diff --git a/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/core/HttpSpace.java b/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/core/HttpSpace.java
index 63cffd03f..939986bc0 100644
--- a/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/core/HttpSpace.java
+++ b/nb-adapters/adapter-http/src/main/java/io/nosqlbench/adapter/http/core/HttpSpace.java
@@ -16,6 +16,9 @@
 
 package io.nosqlbench.adapter.http.core;
 
+import io.nosqlbench.adapter.http.HttpDriverAdapter;
+import io.nosqlbench.nb.api.engine.metrics.DeltaHdrHistogramReservoir;
+import io.nosqlbench.nb.api.engine.metrics.instruments.NBMetricHistogram;
 import io.nosqlbench.nb.api.labels.NBLabeledElement;
 import io.nosqlbench.nb.api.labels.NBLabels;
 import io.nosqlbench.nb.api.config.standard.ConfigModel;
@@ -39,24 +42,25 @@ import java.util.Locale;
 public class HttpSpace implements NBLabeledElement {
     private final static Logger logger = LogManager.getLogger(HttpSpace.class);
 
-    private final NBComponent parent;
+    private final HttpDriverAdapter parentAdapter;
     private final String name;
     private final NBConfiguration cfg;
+    public NBMetricHistogram statusCodeHistogram;
     private HttpConsoleFormats console;
     private HttpClient.Redirect followRedirects;
     private Duration timeout;
     private long timeoutMillis;
     private final HttpClient httpclient;
     private int hdrDigits;
-    private HttpMetrics httpMetrics;
     private boolean diagnosticsEnabled;
 
 
-    public HttpSpace(NBComponent parent, String spaceName, NBConfiguration cfg) {
-        this.parent = parent;
+    public HttpSpace(HttpDriverAdapter parentAdapter, String spaceName, NBConfiguration cfg) {
+        this.parentAdapter = parentAdapter;
         this.name = spaceName;
         this.cfg = cfg;
         applyConfig(cfg);
+        this.statusCodeHistogram = parentAdapter.statusCodeHistogram;
         this.httpclient = newClient();
     }
 
@@ -79,10 +83,9 @@ public class HttpSpace implements NBLabeledElement {
             );
         this.timeout = Duration.ofMillis(cfg.get("timeout", long.class));
         this.timeoutMillis = cfg.get("timeout", long.class);
-        this.httpMetrics = new HttpMetrics(parent, this);
 
         this.console = cfg.getOptional("diag").map(s -> HttpConsoleFormats.apply(s, this.console))
-            .orElseGet(() -> HttpConsoleFormats.apply(null,null));
+            .orElseGet(() -> HttpConsoleFormats.apply(null, null));
 
         this.diagnosticsEnabled = console.isDiagnosticMode();
 
@@ -105,10 +108,6 @@ public class HttpSpace implements NBLabeledElement {
         return name;
     }
 
-    public HttpMetrics getHttpMetrics() {
-        return httpMetrics;
-    }
-
     public boolean isDiagnosticMode() {
         return diagnosticsEnabled;
     }
@@ -124,18 +123,15 @@ public class HttpSpace implements NBLabeledElement {
                 .setDescription("Whether to follow redirects. Normal redirects are those which do not " +
                     "redirect from HTTPS to HTTP.")
             )
-            .add(Param.optional(List.of("diag","diagnostics"), String.class)
+            .add(Param.optional(List.of("diag", "diagnostics"), String.class)
                 .setDescription("Print extended diagnostics. This option has numerous" +
                     " possible values. See the markdown docs for details. (nb help http)")
             )
-            .add(Param.defaultTo("timeout", 1000L*60L*15L) // 15 minutes
+            .add(Param.defaultTo("timeout", 1000L * 60L * 15L) // 15 minutes
                 .setDescription("How long to wait for requests before timeout out. Default is forever."))
             .add(Param.defaultTo("hdr_digits", 4)
                 .setDescription("number of digits of precision to keep in HDR histograms"))
             .asReadOnly();
-
     }
 
-
-
 }
diff --git a/nb-apis/adapters-api/src/main/java/io/nosqlbench/adapters/api/templating/ParsedOp.java b/nb-apis/adapters-api/src/main/java/io/nosqlbench/adapters/api/templating/ParsedOp.java
index 04de0e633..1d7f43595 100644
--- a/nb-apis/adapters-api/src/main/java/io/nosqlbench/adapters/api/templating/ParsedOp.java
+++ b/nb-apis/adapters-api/src/main/java/io/nosqlbench/adapters/api/templating/ParsedOp.java
@@ -70,7 +70,7 @@ import java.util.function.LongFunction;
  * specification tests under the workload_definition folder of the adapters-api module.
  * </P>
  *
- *
+ * <HR/>
  * <H2>Op Template Parsing</H2>
  * <OL>
  * <LI>Rule #1: All op templates are parsed into an internal normalized structure which contains:
@@ -92,36 +92,41 @@ import java.util.function.LongFunction;
  * The net effect of these rules is that the NoSQLBench driver developer may safely use functional forms to access data
  * in the op template, or may decide that certain op fields must only be provided in a static way per operation.
  * </P>
- *
+ * <HR/>
  * <H2>Distinguishing Op Payload from Op Config</H2>
  * <P>When a user specifies an op template, they may choose to provide only a single set of op fields without
  * distinguishing between config or payload, or they may choose to directly configure each.
- * <H4>Example:</H4>
+ *
  * <PRE>{@code
  * ops:
- * # both op and params explicitly named
- * op1:
- * op:
- * opfield1: value1
- * params:
- * param2: value2
- * # neither op field nor params named, so all assumed to be op fields
- * op2:
- * opfield1: value1
- * param2: value2
- * # in this case, if param2 is meant to be config level,
- * # it is a likely config error that should be thrown to the user
- * # only op field explicitly named, so remainder automatically pushed into params
- * op3:
- * op:
- * opfield1: value1
- * param2: value2
- * # only params explicitly named, so remainder pushed into op payload
- * op4:
- * params:
- * param2: value2
- * opfield1: value1
- * }</PRE>
+ *
+ *  # both op and params explicitly named
+ *  op1:
+ *   op:
+ *    opfield1: value1
+ *   params:
+ *    param2: value2
+ *
+ *  # neither op field nor params named, so all assumed to be op fields
+ *  op2:
+ *   opfield1: value1
+ *   param2: value2
+ *
+ *  # in this case, if param2 is meant to be config level,
+ *  # it is a likely config error that should be thrown to the user
+ *  # only op field explicitly named, so remainder automatically pushed into params
+ *  op3:
+ *   op:
+ *    opfield1: value1
+ *    param2: value2
+ *
+ *  # only params explicitly named, so remainder pushed into op payload
+ *  op4:
+ *   params:
+ *    param2: value2
+ *   opfield1: value1
+ * }</PRE></P>
+ *
  * <p>
  * All of these are considered valid constructions, and all of them may actually achieve the same result.
  * This looks like an undesirable problem, but it serves to simplify things for users in one specific way: It allows
@@ -135,37 +140,37 @@ import java.util.function.LongFunction;
  * <HR></HR>
  * <H2>Design Invariants</H2>
  *
- * <P>The above rules imply invariants, which are made explicit here. {@link ParsedOp}.</P>
+ * <P>The above rules imply invariants, which are made explicit here.</P>
  *
- * <P><UL>
+ * <H4>Single Purpose Fields</H4>
+ * <P><EM>You may not use an op field name or parameter name for more than one purpose.</EM></P>
  *
- * <LI><EM>You may not use an op field name or parameter name for more than one purpose.</EM>
- * <UL>
- * <LI>Treat all parameters supported by a driver adapter and it's op fields as a globally shared namespace, even if it
- * is not.
- * This avoids creating any confusion about what a parameter can be used for and how to use it for the right thing in
- * the right place.
- * For example, you may not use the parameter name `socket` in an op template to mean one thing and then use it
+ * <H4>Shared Namespace</H4>
+ * <P><EM>Treat all parameters supported by a driver adapter and it's op fields as a globally shared namespace, even
+ * if it is not.</EM></P>
+ *
+ * <P>This avoids creating any confusion about what a parameter can be used for and how to use it for the right thing in
+ * the right place. For example, you may not use the parameter name `socket` in an op template to mean one thing and then use it
  * at the driver adapter level to mean something different. However, if the meaning is congruent, a driver developer
  * may choose to support some cross-cutting parameters at the activity level. These allowances are explicit,
- * however, as each driver dictates what it will allow as activity parameters.
- * </LI>
- * </UL>
- * </LI>
+ * however, as each driver dictates what it will allow as activity parameters.</P>
+ *
+ * <H3>Layered Resolution</H3>
+ *
+ * <P><EM>Users may specify op payload fields within op params or activity params as fallback config sources in that
+ * order.</EM></P>
  *
- * <LI><EM>Users may specify op payload fields within op params or activity params as fallback config sources in that
- * order.</EM>
  * <UL>
  * <LI>IF a name is valid as an op field, it must also be valid as such when specified in op params.</LI>
  * <LI>If a name is valid as an op field, it must also be valid as such when specified in activity params, within the
  * scope of {@link ParsedOp}</LI>
  * <LI>When an op field is found via op params or activity params, it may NOT be dynamic. If dynamic values are intended
- * to be provided
- * at a common layer in the workload, then bindings support this already.</LI>
+ * to be provided at a common layer in the workload, then bindings or template variables support this already.</LI>
  * </UL>
  * </LI>
  *
- * <LI><EM>You must access non-payload params via Config-oriented methods.</EM>
+ * <H3>Configuration Fields</H3>
+ * <EM>You must access non-payload params via Config-oriented methods.</EM>
  * <UL>
  * <LI>Op Templates contain op payload data and op configs (params, activity params).</LI>
  * <LI>You must use only {@link ParsedOp} getters with "...Config..." names, such as
@@ -176,56 +181,49 @@ import java.util.function.LongFunction;
  * </UL>
  * </LI>
  *
- * <LI><EM>The user must be warned when a required or optional config value is missing from op params (or activity
- * params), but a value
- * of the same name is found in op payload fields.</EM>
- * <UL>
- * <LI>If rule #1 is followed, and names are unambiguous across the driver, then it is almost certainly a configuration
- * error.</LI>
- * </UL>
- * </LI>
+ * <H3>Sanity Checks</H3>
  *
- * <LI><EM>When both an op payload field and a param field of the same name are defined through cascading configuration
- * of param fields,
- * the local op payload field takes precedence.</EM>
+ * <P><EM>The user must be warned when a required or optional config value is missing from op params (or activity
+ * params), but a value of the same name is found in op payload fields.</EM>
+ * If rule #1 is followed, and names are unambiguous across the driver, then it is almost certainly a configuration
+ * error.</P>
+ *
+ * <H3>Precedence</H3>
+ * <P>The order of precedence for values is:
  * <UL>
- * <LI>This is an extension of the param override rules which say that the closest (most local) value to an operation is
- * the one that takes precedence.</LI>
- * <LI>In practice, there will be no conflicts between direct static and dynamic fields, but there will be possibly
- * between
- * static or dynamic fields and parameters and activity params. If a user wants to promote an activity param as an
- * override to existing op fields,
- * template variables allow for this to happen gracefully. Otherwise, the order of precedence is 1) op fields 2) op
- * params 3) activity params.</LI>
- * </UL>
- * </LI>
+ *   <LI>op payload fields</LI>
+ *   <LI>op param fields</LI>
+ *   <LI>activity params (when enabled, see below)</LI>
  * </UL>
  * </P>
  *
+ * <H3>Enabling Activity Params</H3>
+ * <P>If a user wants to allow an activity param as an default for an fields, they must publish the op field
+ * name in the configuration model for the activity. Otherwise it is an error to specify the value at the activity
+ * level.</P>
+ *
  * <HR></HR>
  *
  * <H2>Op Payload Forms</H2>
  * Field values can come from multiple sources. These forms and any of their combinations are supported.
  *
  * <H3>Static Op Fields</H3>
- * <H4>Example:</H4>
  * <PRE>{@code
  * op:
- * field1: value1
- * field2:
- * map3:
- * key4: value4
- * map5:
- * key6: value6
- * field7: false
- * field8: 8.8
+ *  field1: value1
+ *  field2:
+ *   map3:
+ *    key4: value4
+ *    map5:
+ *     key6: value6
+ *  field7: false
+ *  field8: 8.8
  * }</PRE>
  * <p>
  * As shown, any literal value of any valid YAML type, including structured values like lists or maps are accepted as
  * static op template values. A static value is any value which contains zero bind points at any level.
  *
  * <H3>Dynamic Op Fields with Binding References</H3>
- * <H4>Example:</H4>
  * <PRE>{@code
  * op:
  * field1: "{binding1}"
@@ -247,34 +245,32 @@ import java.util.function.LongFunction;
  * null values invalid for ANY op template value.</P>
  *
  * <H3>Dynamic Op Fields with Binding Definitions</H3>
- * <H4>Example:</H4>
- *
  * <PRE>{@code
  * op:
- * field1: "{{NumberNameToString()}}"
- * field2: "value is: {{NumberNameToString()}}"
+ *  field1: "{{NumberNameToString()}}"
+ *  field2: "value is: {{NumberNameToString()}}"
  * }
  * </PRE>
  * <p>
  * This form has exactly the same effect as the previous example as long as your bindings definitions included:
  * <PRE>{@code
  * bindings:
- * binding1: NumberNameToString();
+ *  binding1: NumberNameToString();
  * }</PRE>
  *
  * <H3>Dynamic Op Fields with Structure</H3>
- * <H4>Example:</H4>
  *
  * <PRE>{@code
- * field1:
- * k1: "{binding1}
- * k2: "literal value"
- * field2:
- * - "value3"
- * - "{binding4}"
- * - "a value: {binding5}"
- * - "{{NumberNameToString}}"
- * - "a value: {{NumberNameToString()}}"
+ * op:
+ *  field1:
+ *   k1: "{binding1}
+ *   k2: "literal value"
+ *  field2:
+ *   - "value3"
+ *   - "{binding4}"
+ *   - "a value: {binding5}"
+ *   - "{{NumberNameToString}}"
+ *   - "a value: {{NumberNameToString()}}"
  * }</PRE>
  *
  * <P>This example combines the previous ones with structure and dynamic values. Both field1 and field2 are dynamic,
@@ -286,15 +282,14 @@ import java.util.function.LongFunction;
  * configure your binding definitions thusly.</P>
  *
  * <H3>Op Template Params</H3>
- * <H4>Example:</H4>
  * <PRE>{@code
  * params:
- * prepared: true
+ *  prepared: true
  * ops:
- * op1:
- * field1: value1
- * params:
- * prepared: false
+ *  op1:
+ *   field1: value1
+ *   params:
+ *    prepared: false
  * }</PRE>
  * <p>
  * The params section are the first layer of external configuration values that an op template can use to distinguish
@@ -308,7 +303,6 @@ import java.util.function.LongFunction;
  * down to each block and then down to each statement.
  *
  * <H3>Activity Params</H3>
- * <H4>Example:</H4>
  * <PRE>{@code
  * ./nb run driver=... workload=... cl=LOCAL_QUORUM
  * }</PRE>
@@ -317,6 +311,19 @@ import java.util.function.LongFunction;
  * another fallback source for configuration parameters. The {@link ParsedOp} implementation will automatically look
  * in the activity parameters if needed to find a missing configuration parameter, but this will only work if
  * the specific named parameter is allowed at the activity level.</P>
+ *
+ * <HR/>
+ * <H2>Alternate Names</H2>
+ * <P>Sometimes you may need to support more than one name for the same purpose. In such cases, there are helper
+ * methods which can be used to reduce from a set of possible field names to a single one.
+ * <UL>
+ *     <LI>{@link #requiredFieldOf(String...)} and {@link #requiredFieldOf(List)} will find exactly one field within the set of
+ *     possible fields.
+ *     Zero or more than one will throw an error.</LI>
+ *     <LI>{@link #optionalFieldOf(String...)} and {@link #optionalFieldOf(List)} will find exactly zero or one
+ *     field within the set of possible fields. More than one will throw an error.</LI>
+ * </UL>
+ * </P>
  */
 public class ParsedOp extends NBBaseComponent implements LongFunction<Map<String, ?>>, NBComponent, StaticFieldReader, DynamicFieldReader {
 
@@ -571,15 +578,6 @@ public class ParsedOp extends NBBaseComponent implements LongFunction<Map<String
     }
 
 
-    public <T> Optional<T> getOptionalStaticValue(List<String> fieldNames, Class<T> classOfT) {
-        for (String field : fieldNames) {
-            if (isStatic(field)) {
-                return Optional.ofNullable(tmap.getStaticValue(field, classOfT));
-            }
-        }
-        return Optional.empty();
-    }
-
     public <T> Optional<T> takeOptionalStaticValue(String field, Class<T> classOfT) {
         return Optional.ofNullable(tmap.takeStaticValue(field, classOfT));
     }
@@ -919,24 +917,6 @@ public class ParsedOp extends NBBaseComponent implements LongFunction<Map<String
         return lfa;
     }
 
-    public <FA, FE> LongFunction<FA> enhanceFunc(
-        LongFunction<FA> func,
-        List<String> fields,
-        Class<FE> type,
-        BiFunction<FA, FE, FA> combiner
-    ) {
-        for (String field : fields) {
-            if (isDefined(field)) {
-                LongFunction<FE> fieldEnhancerFunc = getAsRequiredFunction(field, type);
-                LongFunction<FA> lfa = l -> combiner.apply(func.apply(l), fieldEnhancerFunc.apply(l));
-                return lfa;
-            }
-        }
-        throw new OpConfigError("One of the op fields from " + fields + " is required, but none was found " +
-            "in the op template named '" + this.getName() + "'");
-    }
-
-
     /**
      * <p>Enhance a {@link Function} with a named optional function IFF it exists.</p>
      *
@@ -969,23 +949,6 @@ public class ParsedOp extends NBBaseComponent implements LongFunction<Map<String
         return lfa;
     }
 
-    public <FA, FE> LongFunction<FA> enhanceFuncOptionally(
-        LongFunction<FA> func,
-        List<String> fields,
-        Class<FE> type,
-        BiFunction<FA, FE, FA> combiner
-    ) {
-        for (String field : fields) {
-            Optional<LongFunction<FE>> fieldEnhancerFunc = getAsOptionalFunction(field, type);
-            if (fieldEnhancerFunc.isPresent()) {
-                LongFunction<FE> feLongFunction = fieldEnhancerFunc.get();
-                LongFunction<FA> lfa = l -> combiner.apply(func.apply(l), feLongFunction.apply(l));
-                return lfa;
-            }
-        }
-        return func;
-    }
-
 
     public static enum SubOpNaming {
         SubKey,
@@ -1241,4 +1204,38 @@ public class ParsedOp extends NBBaseComponent implements LongFunction<Map<String
     }
 
 
+
+    private String oneFieldOrNull(List<String> fields) {
+        int count = 0;
+        String found = null;
+        for (String field : fields) {
+            if (isDefined(field)) {
+                if (found == null) {
+                    found = field;
+                } else {
+                    throw new OpConfigError(STR."exactly one of \{fields} was required, but it was found as both \{found} and \{field}");
+                }
+            }
+
+        }
+        return found;
+    }
+
+    public Optional<String> optionalFieldOf(List<String> fields) {
+        return Optional.ofNullable(oneFieldOrNull(fields));
+    }
+    public Optional<String> optionalFieldOf(String... fields) {
+        return Optional.ofNullable(oneFieldOrNull(List.of(fields)));
+    }
+    public String requiredFieldOf(String... fields) {
+        return requiredFieldOf(List.of(fields));
+    }
+    public String requiredFieldOf(List<String> fields) {
+        String field = oneFieldOrNull(fields);
+        if (field==null) {
+            throw new OpConfigError(STR."no fields were found with name in (\{fields}) for op template \{this}");
+        }
+        return field;
+    }
+
 }
diff --git a/nb-apis/nb-api/src/main/java/io/nosqlbench/nb/api/components/core/NBBaseComponentMetrics.java b/nb-apis/nb-api/src/main/java/io/nosqlbench/nb/api/components/core/NBBaseComponentMetrics.java
index 9e5ceda89..14348e523 100644
--- a/nb-apis/nb-api/src/main/java/io/nosqlbench/nb/api/components/core/NBBaseComponentMetrics.java
+++ b/nb-apis/nb-api/src/main/java/io/nosqlbench/nb/api/components/core/NBBaseComponentMetrics.java
@@ -38,7 +38,8 @@ public class NBBaseComponentMetrics implements NBComponentMetrics {
             lock.lock();
             String openMetricsName = metric.getLabels().linearizeAsMetrics();
             if (metrics.containsKey(openMetricsName)) {
-                throw new RuntimeException("Can't add the same metric by label set to the same live component:" + openMetricsName);
+                throw new RuntimeException("Can't add the same metric by label set to the same live component:" +
+                    " this:" + this.toString());
             }
             metrics.put(openMetricsName,metric);
             for (MetricRegistryListener listener : listeners) {
diff --git a/nb-apis/nb-api/src/main/java/io/nosqlbench/nb/api/components/core/NBComponentProps.java b/nb-apis/nb-api/src/main/java/io/nosqlbench/nb/api/components/core/NBComponentProps.java
index 2546fab01..79b4eeb2e 100644
--- a/nb-apis/nb-api/src/main/java/io/nosqlbench/nb/api/components/core/NBComponentProps.java
+++ b/nb-apis/nb-api/src/main/java/io/nosqlbench/nb/api/components/core/NBComponentProps.java
@@ -20,6 +20,7 @@ import java.util.Optional;
 
 public interface NBComponentProps {
     String SUMMARY = "summary";
+    String HDRDIGITS = "hdr_digits";
 
     Optional<String> getComponentProp(String name);
     NBComponentProps setComponentProp(String name, String value);
diff --git a/nb-engine/nb-engine-core/pom.xml b/nb-engine/nb-engine-core/pom.xml
index 1db09de7b..4e18f7527 100644
--- a/nb-engine/nb-engine-core/pom.xml
+++ b/nb-engine/nb-engine-core/pom.xml
@@ -142,6 +142,7 @@
                         <groupId>org.apache.maven.plugins</groupId>
                         <artifactId>maven-surefire-plugin</artifactId>
                         <configuration>
+                            <argLine>--enable-preview @{argLine}</argLine>
                             <groups>perf</groups>
                         </configuration>
                     </plugin>
diff --git a/nb-virtdata/pom.xml b/nb-virtdata/pom.xml
index 4dfc1e347..f4e201222 100644
--- a/nb-virtdata/pom.xml
+++ b/nb-virtdata/pom.xml
@@ -56,6 +56,7 @@
                     </execution>
                 </executions>
                 <configuration>
+                    <argLine>--enable-preview @{argLine}</argLine>
                     <additionalClasspathElements>
                         <additionalClasspathElement>${project.basedir}/target/virtdata-userlibs-${project.version}.jar
                         </additionalClasspathElement>
diff --git a/nb-virtdata/virtdata-api/src/main/java/io/nosqlbench/engine/api/templating/ParsedTemplateMap.java b/nb-virtdata/virtdata-api/src/main/java/io/nosqlbench/engine/api/templating/ParsedTemplateMap.java
index dbe8b7c25..91958258a 100644
--- a/nb-virtdata/virtdata-api/src/main/java/io/nosqlbench/engine/api/templating/ParsedTemplateMap.java
+++ b/nb-virtdata/virtdata-api/src/main/java/io/nosqlbench/engine/api/templating/ParsedTemplateMap.java
@@ -302,7 +302,7 @@ public class ParsedTemplateMap implements LongFunction<Map<String, ?>>, StaticFi
         } else if (isConfig(field)) {
             return getConfig(field);
         }
-        logger.warn("static field '{}' was requested, but it does not exist", field);
+//        logger.warn("static field '{}' was requested, but it does not exist", field);
         return null;
     }
 
diff --git a/nb5-proof/pom.xml b/nb5-proof/pom.xml
index 101f582e2..f22f81ff6 100644
--- a/nb5-proof/pom.xml
+++ b/nb5-proof/pom.xml
@@ -94,6 +94,7 @@
               </execution>
             </executions>
             <configuration>
+                <argLine>--enable-preview @{argLine}</argLine>
               <forkCount>1</forkCount>
               <reuseForks>false</reuseForks>
               <includes>
diff --git a/nbr-demos/pom.xml b/nbr-demos/pom.xml
index 272924414..26168d8b3 100644
--- a/nbr-demos/pom.xml
+++ b/nbr-demos/pom.xml
@@ -75,6 +75,7 @@
                     </execution>
                 </executions>
                 <configuration>
+                    <argLine>--enable-preview @{argLine}</argLine>
                     <parallel>methods</parallel>
                     <!--                    <additionalClasspathElements>-->
                     <!--                        <additionalClasspathElement>${project.basedir}/target/virtdata-userlibs-${project.version}.jar-->
diff --git a/nbr/src/test/java/io/nosqlbench/cli/testing/ExitStatusIntegrationTests.java b/nbr/src/test/java/io/nosqlbench/cli/testing/ExitStatusIntegrationTests.java
index 334b6ef06..58bb0a002 100644
--- a/nbr/src/test/java/io/nosqlbench/cli/testing/ExitStatusIntegrationTests.java
+++ b/nbr/src/test/java/io/nosqlbench/cli/testing/ExitStatusIntegrationTests.java
@@ -29,12 +29,13 @@ class ExitStatusIntegrationTests {
 
     private final static String JARNAME = "target/nbr.jar";
 
+
     @Test
     void testExitStatusOnBadParam() {
         ProcessInvoker invoker = new ProcessInvoker();
         invoker.setLogDir("logs/test");
         ProcessResult result = invoker.run("exitstatus_badparam", 15,
-                java, "-jar", JARNAME, "--logs-dir", "logs/test/badparam/",
+                java, "--enable-preview", "-jar", JARNAME, "--logs-dir", "logs/test/badparam/",
                 "badparam"
         );
         assertThat(result.exception).isNull();
@@ -48,7 +49,7 @@ class ExitStatusIntegrationTests {
         ProcessInvoker invoker = new ProcessInvoker();
         invoker.setLogDir("logs/test");
         ProcessResult result = invoker.run("exitstatus_initexception", 15,
-                java, "-jar", JARNAME, "--logs-dir", "logs/test/initerror", "run",
+                java, "--enable-preview", "-jar", JARNAME, "--logs-dir", "logs/test/initerror", "run",
                 "driver=diag", "op=initdelay:initdelay=notanumber"
         );
         assertThat(result.exception).isNull();
@@ -64,7 +65,8 @@ class ExitStatusIntegrationTests {
 
         // Forcing a thread exception via basic command issue.
         ProcessResult result = invoker.run("exitstatus_threadexception", 30,
-                "java", "-jar", JARNAME, "--logs-dir", "logs/test/threadexcep", "--logs-level", "debug", "run",
+                "java", "--enable-preview", "-jar", JARNAME, "--logs-dir", "logs/test/threadexcep", "--logs-level",
+            "debug", "run",
                 "driver=diag", "cyclerate=10", "not_a_thing", "cycles=100", "-vvv"
         );
         String stdout = String.join("\n", result.getStdoutData());
@@ -77,7 +79,7 @@ class ExitStatusIntegrationTests {
         ProcessInvoker invoker = new ProcessInvoker();
         invoker.setLogDir("logs/test");
         ProcessResult result = invoker.run("exitstatus_asyncstoprequest", 60,
-                "java", "-jar", JARNAME, "--logs-dir", "logs/test/asyncstop", "--logs-level", "debug", "run",
+                "java", "--enable-preview", "-jar", JARNAME, "--logs-dir", "logs/test/asyncstop", "--logs-level", "debug", "run",
                 "driver=diag", "threads=2", "cyclerate=10", "op=erroroncycle:erroroncycle=10", "cycles=50", "-vvv"
         );
         assertThat(result.exception).isNull();