Many years ago I heard all the tales of this new substitute black powder developed by Dan Pawlek (?). Dan was still alive then. No fouling, much shooting without the need to clean between shots. Less dense than black powder so more shots per pound. I bought a round cylindrical container of Pyrodex in the pistol granulation for my virtually new Navy Arms Reb revolver in 36 caliber. Loaded my little 36 caliber revolver up. The hang fires were quite long. This had never happened before. I loaded the next cylinder with my customary 3fg Dupont Powder. Firing was instant. I still have what's left of that cylinder of powder to remind of that trip to the range.
You may have a wall hangar, but I do suggest that you try some 3fg GOEX or Olde Eynsford. Did you have problems previously with real black powder? 20 grains of powder should be potent enough to get the ball down range.