if you're gonna play with extra light bullets, look into berry's 100gr hollow base projectiles, they're hollow base makes it longer so you don't have to load super short.
i ran a czechmate for many years in 3gun and uspsa, pretty much only shot majjor ammo, didn't want to mess with the gun switching loads. but i also didn't want to set up multiple open guns for each game.
but that's what i'd do now if i were starting over. i'd very much consider something like an older sti steelmaster designed to shoot minor, they're lighter for all the non pistol portions of 2 and 3 gun games, and still fast and flat. but now i'd probably go with something designed like the staccato xc or whatever atlas has the shorty comp and put a slide mounted optic on top. that way for the 2/3 gun games you can much more easily run a retention holster.