speed matching for muing

[chesapeake chaney]

I have a sound and non sound rs-3 unit.  I would like to speed match them so i can run the as a 2 engine multiple unit. out of the box they run at completely different speeds.  The sound unit seems to run slower.  I have tried adjusting cv's on the main  and have had to clear them with cv 8 equals 8 numerous times to start over.  Could someone give me an idea on how to proceed. thanks in advance Brian