that is one job you will have to work out.

I have a CVA 12 ga double and I use 100 gr. powder and 1 1/2 oz # 6 shot.that does a good job to 25 to 30 yards. no more than 30 yards.of course getting them in close is the name of the game.

building up a load is the fun part.you just have to start low and go from there.you manule should give you a good starting point.if not start with 50 to 75 gr. powder and 1 oz. shot at 25 yards and go till you get a good pattern.

I dry fire a couple caps, then pour in the powder; an over powder wad ; then (the shot cup) I don't use one(instead of a shot cup,I use another fiber wad).then the shot ; an over shot wad and you ready to go.

others may have other ideas,thats just the way I'ev been doing it for the past 20 years.works for me.