Osayo,
I am increasingly comming to the opinion that the square open top shoulder bags that alot of us use, were in the period NOT shot bags.
There are too many references and drawings of Natives with these bags and no horn and no weapon.
Likewise, there are drawings of armed natives with no bag or using a slit pouch.
I believe natives did not carry ball and accessories like the whites did. A slit pouch would be just the right size for a few balls and wads or shot. There are drawings of such with the slit pouch hung over the horn.
I am thinking the decorated square bags that are seen are more like "possables" bags to be used as pockets for all those little things that one would commonly carry.
I will pour powder in my palm and load from there for reenactments, But I am told there are some places that donot allow that.
If i were to have to use paper cartridges, i would want a pouch i could get into easy and it would definetly have a flap to protect from sparks, But i would also not consider the practice period correct.