Have you tried this?
I use the pan and cookie cutter method and the lube that works well for me is also cheap and readily available at any hardware store. You might not like it because it's sticky and soft. But it should work well for black-powder cartidges. I use it exclusively with all powders in 45 Colt. It's wax toilet-bowl sealing rings. Buy the cheapest ones. Melt them with other ingredients and make your own custom recipe. Or just use it as is like I do.