i'll keep the comb/recoil issue in mind, kurt. i'm used to shooting hot magnums from a rifle with a high comb, so we'll see how it goes.
i've been tossing the .50/.54/.58 issue around in my head, and since i'm going to be getting molds for my blackpowder guns, ammunition isn't a problem. wads, also, aren't a problem, fabric stores and a plug-cutter solve that issue(i have no problem with the DIY approach). i think it's more a suitability issue, kind of like how i don't go deer hunting with my .300 magnum, but with the .44 mag carbine. it's better suited to the job, overall. of course, the .44 is suited to nearly any job, but the .300 does pack that greater reach and power for situations where it is indeed suited.
the .50 will do the job(as it did the job for a lot of guys many moons ago), and if i feel it's not up to it, i'll swap up to a .54 barrel and rock that out.