I've done the 7 drake Barrows thing many a time. My record was doing so was 9 minutes
I even got a banded one last season but those dang commons seem to elude me. I centered one last year three times and he just flew off into the sunset
Where I hunt in WA there seem to be only about 0.5% of the GE's we decoy and see. Like with everything it falls back on LOCATION, LOCATION, LOCATION.
No matter where they hit the water on their backs, those are some fine looking birds to put on the wall or shelf.