Traditioally most like the tightest pattern they can get, so full or extra full would be the way to go. You have to remember that pound for pound, the turkey is one of the toughest birds/animals on the planet. With that you want as many pellets in the kill zone (head and neck) as you can get.

As for ammo, you supernova should shoot 3 1/2 shells. That is what I would use. The pay load will be much greater when it hits the bird. For shot size, either 2's or 4's. Again, if it were me, I would lean toward the 2's because they will give you a little more at longer distances. What ever you buy, you should pattern your gun at different distances to see what will give the best pattern.