^ pretty much it, in a nutshell.

You'd be better off trying to rebuild the Coliseum.

I want to amend what I said earlier that various mechanics suggested this and that, when really it didn't need anything. What they likely suggested was the result of their own trial and errors over time, because everyone I talked to had a different approach.

Spinz, who used to post here, had a very reliable setup of Syncro II on his Team Raleigh, and I bought it. I got it working on a Cinelli and then my brother-in-law made the mistake of thinking it should work "just like his DA 2x6 indexed." He then submitted it to doom: took it to a mechanic. My setup had the correct insert, freewheel, chain, shifters, RD, "B" setting, you name it. The mechanic promptly took off the Athena RD for a Chorus, kept the Athena RD, and declared "it won't ever work." I eventually took the group off for an 8-sp Chorus Ergo setup, which is still working fine, but the bike, with chrome lugs, etc, looked better with the polished stuff vs. the satin Chorus.