Your index finger and a 1 lb. can of plain Crisco. Dip your finger in and get some on the end, smear into the hollow base of the Minie Ball - then repeat with remaining Minie balls needing lube. It's worked for years for N-SSA shooting of the .58 caliber rifled musket musket and other rifled muskets utilizing hollow base Minies. I have fired tens of thousands of them lubed that way over the past 50 years and they work just fine in a number of original rifled muskets as well as reproductions. There is no need to lube what most people would call the "lube grooves" on a Minie Ball.
The purpose of any BP lube is to keep the fouling soft - the Crisco does the job just fine. Good luck and have fun.
If you want to pre-measure your loads for your rifled musket - go to the N-SSA site and click on the sutler page. Sutlers such as The Winchester Sutler, Lodgewood mfg., etc. carry plastic tubes just for that purpose. Pour you measured charge in, grease the hollow base of the Minie with Crisco and put the Minie in the top of the tube nose first as a "stopper". When ready to load, pull the Minie out, dump your charge in, insert the Mine and ram home - cap and fire. With practice, you should be able to get 3 shots per minute.