The problem is, like women, shotguns are fickle and choosy. What mines likes, yours may not. There are really only three good ways to go about this:

1) The Buddy Method - team up with some of your friends who are in the same situation as you. Helps to loiter around the gunshop for an afternoon a week or two before the season. Everyone buys a box of different stuff and you all split the boxes. Two each, Five Each, whatever works it out.

2) Lucky Method - You buy one box, pattern it, and hope it works. If it will do it everytime at 40, I'd for sure call it good enough. But you never know if that magic load is just the next shelf down...

3) All-In Method - Buy 'em all, and shoot 'em all. The results speak for themselves.