Man, we all liked to talk about Miyatas.
I have Exage stuff and Biopace on a couple of bikes...much love from me.
I have gone from a 6 to 7 freewheel, no problems. Or, you could use a ultra-7 freewheel, but it's a pricey alternative, + chain.
As to brifters, you're on your own. I hate brifters, but each to their own.