"Everthing else being equal, the 12 would have a superior pattern to the 16, and the 16 would be superior to the 20."

I'm not so sure about that. I'm not a stat geek, but if one subscribes to the square load theory as a model of efficiency, then the 16 would have the superior pattern, because 1 oz. in a 16 is its optimum load and the most "square" is it not? We're nitpicking here, but it is something to think about. I could see where 1 oz in a 12 might have 2-3% fewer deformed pellets, but I haven't seen any tests to prove that it patterns better as a result.

As GregSY said however, who cares anyway. The important thing is to just enjoy them.

Imagination is everything. - Einstein