For the Bess, I use 11 gauge card wads. I would build it up with 80 grains of 2fg powder and 100grains (volume) of shot. IF you want a square load, use 100 grains of 1fg.
Powder first. Then I would start a thin over shot card. If the over shot card tends to twist or you don't have a bore sized button on your ram rod, I would use a 1/8" over powder card. Next the shot charge and an over shot card. I would top that with a well lubricated half cushion wad ala the Skychief load. By building the components at the muzzle, it will be easier to ram the shot charge home to the breech.