Good little article. I have a Field London Gun, 12 bore SxS that likes 1F GOEX powder in the amount of 75gr. with 1 1/4ox. 7 1/2's. Wads can be 1/2 a cushion donnaconna wad, or just 1 thin "B" overshot wads on the powder. Patterning is the same.
The gun is cylinder bored, both barrels.

Last July weekend at the local rendezvous, I broke 30 birds straight, with this gun, winning the "trap" portion of the contest. The bores are beautiful on it, with 2 little dimples just visible the chambers on the bottom, from the crown proof stamps on the underside of the barrels. All loads were assembled in 2 1/2" plastic hulls and were roll crimped.

We've found that in muzzleloading smoothbores not having chokes, that putting just 2 thin B wads between the powder and shot, prevents the patterns from pattern do-nutting that happens with heavier wads are blasted into the back of the shot column when the 'load' leaves the muzzle.

We've also found that normally wadded black powder loads fired in choked barrels, usually shoot tighter patterns than the choke designation would suggest.
My 20 bore flinter shoots modified patterns, yet only has about .007" of constriction- Imp Cyl, at best.