I've hunted wildbirds for close to 60 yrs, WA, MT, ND,SD, MN, WI and have never needed more than an ounce 5's and usually hunt with an ounce of 6's(12ga, 16ga and 20ga same load). Some of the longest shots I've taken were with a 20ga shooting cleanup on corporate hunts, you know when everyone else is done shooting dropping the cripples. When gunning for hunt tests 7 1/2 trap loads. I do usually hunt over good pointers or close working flushing dogs.
I'm comfortable with light weight short barreled shotguns and they can give me a 10 yd advantage over someone with a long heavy shotgun, I did shoot true low gun international skeet for years.
Shoot the gun you shoot best from a low gun position, nobody walks through the fields with the gun mounted on their shoulder. Practice on trap or skeet with the gun as your going to carry it in the field.
12ga SxS light at 5 lb 15 oz shooting 1 oz 6's in 2.5" hulls, MT wild birds, The white and brown guy was a hunting machine Pheasants, sharpies, ruffs, woodcock ducks and geese were what he lived for. I took this picture because of the variety of bird coloring , burgundy, gold and black hues.