Brownells used to sell the inserts as a "choke sleeve system" for soldering in. They've been discreetly discontinued. They appear in the index, but not the catalog. Mike Orlen used to advertise that he installed them. I think I'd email Mike directly and ask what the scoop is.
Choke tubes will definitely peel out. I experieneced it when I bought a .745 bore Rem 870 trap gun with a regular (made for .730 bore)choke tube installed. At least when Beretta changed choke systems they made sure they weren't interchangeable.
As to buffering....as I recall it can elevate pressures. How much? Who knows? I know it's fashionable to shoot Damascus barreled guns these days, but buffered loads in an 1887 L.C. Smith? Some of you guys are really adventurous.
