The Crisco reference took me back to my first cartridge reloading with cast. I was a muzzleloader shooter primarily but bought an H&R Shikari 45-70 and a Lyman mold. Since Crisco worked for the muzzleloader I just smeared some on the 45-70 boolit and loaded it. It worked great, even with a healthy dose of 3031.
As to getting the amount of blackpowder in the 32-20 IIRC the original cases were folded head and had more room in them. The area around the primer at the head was not solid so could contain powder.