My reference is my 50 cal Frontier rather than the Pennsylvania, but I'm betting the bores are the same. I'm using a .490 ball with .018 ticking and a tallow-based lube rather than a liquid. It's none too tight, and starts easily with a short starter. I'm sure that if I go ahead and cone the barrel, I won't need a short starter at all.
I bring that up because accuracy-wise, mine is not near as happy with the .490 ball and the commercial .015 patches I tried. They worked, but less fouling and better accuracy with the .018.