Admitently you are shooting a larger payload than I so you should be able to get away with a larger pellet. But in my opinion #6 hevi shot is good for ducks out to 50+ yards #6 HS is about like a heavy load of #2 steel. As for geese #4 hevi is a 50 yard goose load about equivalent to a heavy 12ga 3" #T shot steel loading.