To answer your question, you HAVE to know your bore size. Use a plug to measure it and you don't need an entire set. You can get a few relevant ones off Amazon or go to a local machine shop and have them do it.
Past that, I've seen these barrels vary widely and you'll just be wasting time and money without knowing what that measurement is. With that in hand, there are some basics, Minies need to be .001 under bore size and pure lead. Use real black powder. Use lube made from beeswax/lard/ Use good quality caps- RWS or Scheutzen.