At the moment, Patty and I have sixteen Handis, one Huntsman and three shotguns. All are on their own dedicated frame, and
NONE are tweaked in any way. Along the line, a couple had temporary pivot shims etc. until a proper fitting frame came along.
I try to keep three spare SB2 frames at all times. I buy most of them in my home state and avoid FFL transfers etc. When I buy a barrel, invariably one of the frames will fit well, if not perfectly. If I have one that's ok, but not the way I want it, I try it on the next frame I get. I buy only SB2 frames. In fact, my Huntsman and pistol calibers are on them. Needed? No. Having them all on SB2s gives me a lot more flexibility.
I've got to warn you. There is a hazard in keeping spare frames. When you have them and a couple of stock sets collecting dust, it's real easy to sucker yourself into putting another rifle together.
Keeping three spares is roughly a 300 dollar investment, but I feel it is well worth it.......besides, I like to be tempted
Pete