I'm a competitive shotgunner also. Of course, your example only covers the gamut from IC to Mod, which only covers about 10 yards of difference in range. After saying that, there's not as much difference as people think, as a rule, the difference in pattern diameter between a M and F is somewhere in the 3-4 inches range. The difference in pattern percentage is the density in the center for the most part. I'm not sure any of that makes a huge difference for hunters, if you're shooting upland game at a max of 40 yards, most under 25, just shoot IC, you won't cripple game that you don't center.
