Most of my muzzle loader kills have been with a .50 Hawken and big conicals that kick hard, but a few years ago, I started dabbling with inlines. Last couple of deer I shot with a cheap inline (still gives decent accuracy) the RCBS 225 grain .44 SWC and 70 grains of 777. I put a slip on recoil pad over the rubber buttplate and the rifle is pretty easy on me. I was trying to get a combo together that my youngest son, who is somewhat recoil shy, would use, but he isn't into September deer hunting.
I'd say get an inline, some relatively light pistol bullets and sabots and weight the rifle with some lead shot or something and give it a try.