Well, the .535" RB with a .018" patch loads easily and over 70 grains of FFg, it keeps all the shots into an 8" plate at 60 yards. That'll do for right now, and I'll see if I can convince a deer to catch one next weekend when our ML season starts.
I'll work on different loads after this season is over.
I can see why the smoothbore was a preferred weapon for so many centuries. I shot it 25 times this weekend, no cleaning or swabbing between shots, and it was still loading as easily on shot #25 as it was on shot #1, and still keeping them in the same target zone. That kind of consistency and ease of operation has a lot of merit.