Well, my Brown Bess is .750 and I use a patched .715 round ball in front of 90 grains of FFg. I haven't shot any living creatures with it, but I do use it occasionally to split logs for firewood!
. If your bore is a true .729, I'd say a .690 round ball with a lubed patch of pillow ticking in front of 80-or-so grains of FFg ought to be decisive.
HTH,
vanfunk