The diversity of opinion here reflects a wide diversity in the "tower shoot" experiences. Really, the best answer (I should have mentioned this at the outset) is to ask the shoot manager or folks who've actually attended his shoots.
I'll describe one setup: at the top of a high knoll is an elevated box platform. Platform is 40-50 feet above ground. Top of knoll is easily 60-70 feet elev above perimeter. Circle radius is irregular ranging from approximately 100-150 yds. It is not unusual for birds to pass directly overhead at 50 yds or more, depending on conditions. The last bird I killed at this tower was a 70 yd (not a typo) incomer taken with my full choke 16 ga M-12 and B&Ps in #5. Some percentage of birds never get hit. The goal is to get as many as possible. As tw notes, birds are divided up evenly at end (not according to how many you think you killed). Thus, poaching is not considered bad form - so long as one is safe. Lead duck loads are, indeed, the bomb.
After birds are divided you put your tower gun away, grab a field gun, and walk-up hunt the escapees over your dogs.
Sam
