You could contact Mr. Pat Kaboskey via Lodgewood manufacturing up in Wisconsin. He can sell you a sample of sized Minies. You want to find a close-fit, like within a couple of thousandths or less to your true bore size. Once you figure that out, you can then start looking for moulds, lead, a furnace for smelting, and other odds and ends, or buy some bullets sized to that size.
I'm not a super-skirmisher marksman by any stretch. I make my own lube out of mutton tallow and bees wax. These days, I'm usually using a 1 to 1 ratio, with a little olive oil to keep it smooth. I put this concoction in a double boiler and dip the bullet skirt stuck into the mouth of my cartridge tubes one at a time, but I've also "pan lubed" them by putting them all on a plate and pouring the molten lubricant on them until it dries.
I've finally decided on a model for the smooth-bore .69 caliber North Carolina so-called "Nessler" bullet cartridges after failing to find how the actual cartridges were made. But that is experimental archaeology and not target shooting or skirmishing. I'll be using a 1 part wax to three part tallow mix for those.