That is just like what hair color on a lady produces the best wife (brunette) or the best girlfriend (blonde) or who makes the best truck (chevy) or even the best import truck (toyota).

But the answer is #6 shot. I've never used anything but #6s. Patterned plenty of everything, but #6s have always done me right. As long as you don't plan on shooting at extreme distances and shoot birds in the head/neck they will lay'em down.

Gotta shoot that gun and see what your gun likes, thats the only way to get an answer and not a bunch of opinions! Good Luck!