In a 12ga, 16ga and 20ga, I'd go with IC. Cover is usually pretty and you need to get on them pretty quickly. To much choke and you could be blowing up birds. In my 28ga, 3/4oz shot, I have mod/full. Works out well because of the less shot. Not so well on longer shots. You might get everything into a 30" circle with it at 30yds, I think that the distences they use. But less shot makes it a less dense pattern. I'm going to try my 410 this year on them too. Also M/F. 1/2 oz shot.