It seems that the distances involved would be a determining factor.Curtis Allinson's long range 451 is the Acme* in muzzle loading rifles.Most shooters of muzzle loading guns in competition use round balls at much closer ranges and some even at distances associated with a pistol.In 1958 I made a light target rifle that was 58 caliber and did well with it and it worked at 100 yards.The price of powder and caps has become a grab and gouge and makes the flint lock more attractive.IF I were going to make a rifle for nothing but making holes in paper it would have a profile like Curtis's Henry either with or without the pistol grip.It would be 40 caliber with
octagon or round barrel or even a 1/3 octagon and 2/3 round and no rib or rod.Set trigger is optional but a fast lock is needed.Sights can be what works for you.This is just my opinion based on nearly 70 years of experience.
*These are specialty rifles and made and almost unique to England,Ireland and Scotland.
Bob Roller
Round balls are the most common.Picket "balls"take special loading methods but have been proven accurate as shown by the test report on the Whitmore rifle once owned by General Grant.Long paper patched bullets were not common in America until the powerful Sharps and Remington breech loaders came along that had patches rolled onto the bullet but there were 2 strip paper patches used with false muzzles that were made to accommodate them.