Hey keith44....I like your calibre selection. The .54 has so much to offer in the way of knockdown power and terminal ballistics. Even though the historic round ball is not considered to be the ideal projectile, in .54 calibre, this projectile type is able to maintain a decent %-tage of its velocity and energy quite well out to and just beyond 100 yards with a nice stout hunting load.
Before I make any type of suggestion...what type of terrain do you plan to be hunting with these proposed firearms?