any news now spanky? at least tell us bullets considered...
as for the .410 compatibility making a difference on hotter rounds, I don't know. you shouldn't have an accuracy problem since your rim would be locked down and the case head flush with the reciever. My plus p just swole the brass a bit without any real performance gains. without a tight enough chamber to keep that pressure going down the barrel it won't do much... but you don't have a cylinder gap and endshake to deal with. it's my understanding that a handi won't blow before a revolver would, so why fear a ruger blackhawk/redhawk load? that brass will swell really easy starting in the high 20,000's. if that's too much swelling, you'll crack brass before getting over thirty, thirty thousand is a lot for an unsupported case! 28,000 is supposed to be what cor-bon USED to aim for (basing that off a 32,000 dangerzone), and that was because blackhawk cylinders in .45 colt were THIN. you're using a thick chamber/barrel.... I don't see why you cannot achieve AT LEAST 20,000 easily. As for whether or not you'll get an accurate "let-off" from the case mouth crimp IF you're swelling brass, I'd be careful. Hand-chamfer those mouths really good every time you load them (I like to chamfer, lube and crimp hard). I'd also be weary of lead bullets for this reason, the inconsistent let off from the casemouth could gaul one side of the bullet and throw off the rifling engagement (or throw shavings from a revolver).
IS YOUR CHAMBER TERRIBLY LOOSE? While .410 compatible chambers are very loose, think of how often you actually have tight chambers to benefit from with a .45 Colt only weapon... none of mine were ever that tight.
be sure your sb2 reciever is g-t-g, keep that latch dry, and I don't know what else can go wrong.