Based on that twist you mention, I would guess the best accuracy would come from a roundball. I have a Traditions with the same twist and shoot 90 grains of Pyrodex or Goex 2f and a patched roundball.
I would guess that your rifle would shoot a similar load and probably better groups. I have never shot a A&H but sure did like the looks of them. I was always under the impression that they were good shooters, and I am sure yours will be as well.