I too use filler over powder and i smear grease over the filler before loading the balls. Bore butter works good but is hard to use if it is to hot or cold. Crisco with just a little bees wax works good. With the lube behind the ball i don't get any hard fouling anywhere even the center pin on my NMA. My NMA target load is 20gr FFF KIK black powder with a 38sp case full of corn meal a little Crisco and bees wax over the filler and a .454 ball. Loading like this i have shot as many as 75 shots and my gun had not fouled out at all. You can push two dry patches though the barrel and it is clean.
If you like heaver loads you can load as usual with powder lubed wad and put a little lube on top the wad before loading the ball.
If you like heaver loads you can load as usual with powder lubed wad and put a little lube on top the wad before loading the ball.