Pure lead will work fine in a black powder Sharps, although the addition of a little wheel wts won't hurt and it may make casting easier. Diameter of the paper cartridge is also not critical in my experience, although I do try to keep it close to bullet diameter just to keep the powder charge where I want it. I use a 1/2 inch dowel rod, wrapped with electrical tape to bring it up to bullet diamater, but I suppose one could sand down a larger size dowel road by chucking it up in a lather or even in a power drill. Lube? SPG is what a lot of cartridge shooters use, but others will work fine. I use beeswax and bear grease, just mixed up thicker than I use for patch lube. I want it to stick to the grooves. As for the paper, I still have a bottle of salpeter laying around that I got at the drugstore. Don't know if you can still get it or not. I would soak bond paper in it then let it dry, and cut out trapezoidal shapes, wrap them around the dowel, then glue the loose end down. Since you are not biting the cartridge like with a muzzleloader paper cartridge, you can make the paper cartridge a little bit thicker and tougher.