If I understand your question I think DeepClone will do fine then change whatever properties needed
<CommandMethod("CloneTextDimStyle")> _
Public Sub CloneTextDimStyle()
Dim doc As Document = Application.DocumentManager.MdiActiveDocument
Dim db As Database = doc.Database
Dim ed As Editor = doc.Editor
Using trx As Transaction = db.TransactionManager.StartTransaction()
Dim dimTbl As DimStyleTable = trx.GetObject(db.DimStyleTableId, OpenMode.ForWrite)
Dim dimBtr As DimStyleTableRecord = trx.GetObject(dimTbl("Standard"), OpenMode.ForRead)
Dim dimMap As New IdMapping
Dim newDimBtr As DimStyleTableRecord = dimBtr.DeepClone(dimTbl, dimMap, True)
newDimBtr.Name = String.Format("{0} (Clone)", dimBtr.Name)
newDimBtr.Dimalt = Not newDimBtr.Dimalt
newDimBtr.Dimaltd = newDimBtr.Dimaltd + 1
dimTbl.Add(newDimBtr)
trx.AddNewlyCreatedDBObject(newDimBtr, True)
trx.Commit()
End Using
End Sub