diff --git a/pkg/transformers/bar.go b/pkg/transformers/bar.go
index f14bdd8ca..79a9abbfe 100644
--- a/pkg/transformers/bar.go
+++ b/pkg/transformers/bar.go
@@ -193,7 +193,7 @@ func NewTransformerBar(
 
 	if doAuto {
 		tr.recordTransformerFunc = tr.processAuto
-		tr.recordsForAutoMode = list.New()
+		tr.recordsForAutoMode = types.NewList[*types.RecordAndContext](10) // XXX size
 	} else {
 		tr.recordTransformerFunc = tr.processNoAuto
 		tr.recordsForAutoMode = nil
@@ -270,9 +270,8 @@ func (tr *TransformerBar) processAuto(
 
 		// The first pass computes lo and hi from the data
 		onFirst := true
-		for e := tr.recordsForAutoMode.Front(); e != nil; e = e.Next() {
-			recordAndContexts := e.Value.(*types.RecordAndContext)
-			record := recordAndContexts.Record
+		for _, recordAndContext := range tr.recordsForAutoMode.Items {
+			record := recordAndContext.Record
 			mvalue := record.Get(fieldName)
 			if mvalue == nil {
 				continue
@@ -300,8 +299,7 @@ func (tr *TransformerBar) processAuto(
 		slo := fmt.Sprintf("%g", lo)
 		shi := fmt.Sprintf("%g", hi)
 
-		for e := tr.recordsForAutoMode.Front(); e != nil; e = e.Next() {
-			recordAndContext := e.Value.(*types.RecordAndContext)
+		for _, recordAndContext := range tr.recordsForAutoMode.Items {
 			record := recordAndContext.Record
 			mvalue := record.Get(fieldName)
 			if mvalue == nil {
@@ -332,10 +330,6 @@ func (tr *TransformerBar) processAuto(
 		}
 	}
 
-	for e := tr.recordsForAutoMode.Front(); e != nil; e = e.Next() {
-		recordAndContext := e.Value.(*types.RecordAndContext)
-		outputRecordsAndContexts.PushBack(recordAndContext)
-	}
-
+	outputRecordsAndContexts.PushBackMultiple(tr.recordsForAutoMode.Items)
 	outputRecordsAndContexts.PushBack(inrecAndContext) // Emit the end-of-stream marker
 }
diff --git a/pkg/transformers/bootstrap.go b/pkg/transformers/bootstrap.go
index dcd319d55..12f769414 100644
--- a/pkg/transformers/bootstrap.go
+++ b/pkg/transformers/bootstrap.go
@@ -96,7 +96,7 @@ type TransformerBootstrap struct {
 
 func NewTransformerBootstrap(nout int64) (*TransformerBootstrap, error) {
 	tr := &TransformerBootstrap{
-		recordsAndContexts: list.New(),
+		recordsAndContexts: types.NewList[*types.RecordAndContext](int(100)), // XXX size
 		nout:               nout,
 	}
 	return tr, nil
diff --git a/pkg/transformers/count_similar.go b/pkg/transformers/count_similar.go
index 8610dda8c..49bfc52a3 100644
--- a/pkg/transformers/count_similar.go
+++ b/pkg/transformers/count_similar.go
@@ -160,6 +160,7 @@ func (tr *TransformerCountSimilar) Transform(
 			}
 		}
 
-		outputRecordsAndContexts.PushBack(inrecAndContext) // Emit the stream-terminating null record
+		// Emit the stream-terminating null record
+		outputRecordsAndContexts.PushBack(inrecAndContext)
 	}
 }
diff --git a/pkg/transformers/fraction.go b/pkg/transformers/fraction.go
index df76fde27..bf64e6928 100644
--- a/pkg/transformers/fraction.go
+++ b/pkg/transformers/fraction.go
@@ -150,7 +150,7 @@ func NewTransformerFraction(
 	doCumu bool,
 ) (*TransformerFraction, error) {
 
-	recordsAndContexts := list.New()
+	recordsAndContexts := types.NewList[*types.RecordAndContext](100) // XXX SIZE
 	sums := make(map[string]map[string]*mlrval.Mlrval)
 	cumus := make(map[string]map[string]*mlrval.Mlrval)
 
diff --git a/pkg/transformers/rename.go b/pkg/transformers/rename.go
index 285535d9e..35f2290a3 100644
--- a/pkg/transformers/rename.go
+++ b/pkg/transformers/rename.go
@@ -134,7 +134,7 @@ type tRegexAndReplacement struct {
 
 type TransformerRename struct {
 	oldToNewNames          *lib.OrderedMap
-	regexesAndReplacements *list.List
+	regexesAndReplacements *types.List[*tRegexAndReplacement]
 	doGsub                 bool
 	recordTransformerFunc  RecordTransformerFunc
 }
@@ -163,7 +163,7 @@ func NewTransformerRename(
 		tr.doGsub = false
 		tr.recordTransformerFunc = tr.transformWithoutRegexes
 	} else {
-		tr.regexesAndReplacements = list.New()
+		tr.regexesAndReplacements = types.NewList[*tRegexAndReplacement](10)
 		for pe := oldToNewNames.Head; pe != nil; pe = pe.Next {
 			regexString := pe.Key
 			regex := lib.CompileMillerRegexOrDie(regexString)
diff --git a/pkg/transformers/sort.go b/pkg/transformers/sort.go
index cba7dbfcc..2102a2abf 100644
--- a/pkg/transformers/sort.go
+++ b/pkg/transformers/sort.go
@@ -309,7 +309,8 @@ type TransformerSort struct {
 	recordListsByGroup *lib.OrderedMap
 	// Map from string to []*lib.Mlrval:
 	groupHeads *lib.OrderedMap
-	spillGroup *list.List // e.g. sort by field "a" -- this is for records lacking a field named "a"
+	// E.g. for sort by field "a", this is for records lacking a field named "a"
+	spillGroup *types.List[*types.RecordAndContext]
 }
 
 func NewTransformerSort(