You're confusing rifle and shotgun shooting. In shotgun shooting, ALL you attention should be on the leading edge of the target, and just a small part of the leading edge if possible. Sights are useful for turkey shooting and a few other such "shotgun" pursuits, but not for skilled wing shooting. Some good wingshooters will conceed the utility of double beads on a rib to ensure proper alignment for long crossing shots, but that's about it. Shotgunning theory for hunters was pretty much perfected about 100 years ago by the Brits. Sights on a shotgun do not change the fundamentals, they just encourage a shooter to "aim" instead of trusting to instinctive point and swing and muscle memory. If you are skeptical, look for successful competitive sporting clays shooters who use red dot sights. There aren't any, for a very good reason. Now if you just want to try something and find out for yourself, or if for some reason you have special needs, by all means go ahead, experimentation is part of what makes shooting so much fun.