In my 12 gauge T/C New Englander I load 80 grains of Jim Shockey Gold 3f, and then push a shot cup down the barrel. Then I put 80 grain of 5&6 (50/50) mixed shot. Then two thin over the shot cards. I found it makes the tightest pattern for some reason. This is a good 25 pushing 30 yard shotgun.

In my Knight TK2000 I load 80 grains of 777 2f, then a 3 inch wad, and a matching cup of 5&6 shot (3 inches) into the wad. Then two over the shot cards. This is a 40 yard shotgun, but I would prefer much closer. I set decoys at 25 yards and normally shoot them on the back side of the decoys.

I did actually get even a tighter pattern when I used a foam over the shot card. But not enough to justify the cost of them.