I like the idea, it's a very good one. Much better than welding and filing. Did you use a self-locking set screw?
One thing I thought about was drilling a hole in the housing, so you could adjust advance without having to disassemble the distributor. Pop a plug in to seal it up.
You find any of those $500 bridgeports lately... :) They are so expensive out here.
Crackedback,the screws that mount the pick-up plate, actually line up pretty well, and you can access the stops by removing one of these screws , or by removing the vacume advance canister. I
just used a dab of thread locker once I got the advance to where I needed it. I'll keep my eyes open for a bridgeport...sometimes they pop up cheap.