Here was a thread I found last year that I found interesting re: shot size.
Interesting also was that at 30-40 yards switching from regular to hypersonic shotshell velocities makes little difference, or at least less difference than increasing shot size.
http://www.duckhuntingchat.com/forum...?f=14&t=110030
Reading through the thread makes me think that the discussions on American boards sound more civilized than some of our threads!