Only other thing I'd throw in on the can stuff is the realities of mounting these things to barrels. I've found that if you are using a mount, rather than direct threat, you can go a bit under the generally recommended .100 of barrel shoulder engagement. The thread pitch I use on most of my guns is 9/16x24. The threads themselves are about .560 so to get to .100 of barrel shoulder you'd be at .660 which is bigger than most sporter barrels.
On a direct thread, I think that in the long run you'd have issues beating the shoulder up if you went much skinner than .100, but if you use a mount and red loctite, I have used a muzzle diameter as small as .620, which is what a lot of #2 barrels finish at at around 20-21". Basically because the mount stays on forever and any abuse of attaching and reattaching the can is taken by the mount itself, rather than the skinny barrel shoulder. Dunno if that makes sense or not. But for that reason I've drifted away from direct threads. If you run heavier barrels it's a toss up on that issue.
