RE: Snow goose??
I read an article in I think it was this month's "American Hunter" magazine from NRA. The cover had Turkey hunting articles advertised.
They stated some of the same challenges about hunting Snow Geese in numbers. They set out an hunted them with over a 1000 decoys and eventually dropped to what they found ideal 400 shell decoys with movement.
That's far more investment and setup/take down time I'dand I think a lot of hunters care for. But it's a possibility if you're really into hunting Snows. They are a real challenge for sure.
Another technique that worked very well this past fall when we found very high numbers in fields and nearby water was to get before light within 1/2 of where they were at in line to where they were going out to feed. We were far enough away from the roost as not to bother them and the were enough coming over that were in range to get good shooting. It's just a great experience to see and hear the great numbers of geese. I wouldn't have believe it until I first hunted them about 8 years ago in Spring in SD. This past fall in ND we layed out on the edge of a picked field they flew over on the way out further for 2 hours while they came off in numbers of 50-100 every minute or so. But we've also seem them come off of a lake in 2-3 waves of 10,000-15,000 eachand they're out to feed in 1/2 hour.