JCS has recommended against the 20ga tubes. I agree but what does he recommend? I'll bet that he recommends 28ga. On the skeet range there is no other gauge that I would prefer to shoot. It breaks birds like a 12ga and the kick is so light that you can shoot all day without fatigue. You might need to load your own for game.
Another benefit of the 28ga is that it is less likely to split your stock behind the side plates.