The senior national sporting clay champion manages the course I shoot at a lot. I have borrowed his guns and shot with him many times. I have never seen him shoot a full choke at any clay. You mean he won a national title by doing it wrong? I guess some folks have the luck of the Irish.Every range I go to the birds fly the same so the same choke and shot that works for you is all you need.
gvw3 has it right.