Hello howdy and welcome,
For me once in traditional, go all the way. Slow twist patched round ball!
Also, I do not know how much money you want to spend, but take a look at Kibler kits. You will have a custom level rifle when done with one of his.
If you need to be lower priced, my stand by is a Lyman Great Plains. Mine has been the most reliable of all my BP firearms.
Enjoy whatever you choose!
Nick