Me and a couple buddies used to go up and hunt back in the mid 90's to early 2000's. Completely and totally different hunting than what I was used to in the "south" of Southern Indiana. The insane numbers of birds and the ability to actually work and have them decoy into the spread regularly was foreign to us public land hunters. Killing a limit wasn't an every hunt thing, but it was a regular thing, and never did we not have tons of action. Back then it was easy to get permission, but towards the end it was getting more difficult as outfitters were sewing up lots of land. The last 2-3 years we ended up in Canada to avoid that, and the hunting there was even better.
We only dry field hunted, both ducks and geese. Ducks came in first light through the next 30 minutes to an hour before the geese would show up. Occasionally we hunted an afternoon field for just ducks. I guess there's still opportunities for freelancers in ND, but it's been so long I just don't know. I would suggest you be open to tying in with another group of hunters doing the same thing in the same area, as that would increase the likelihood of getting permission, and there will be more than enough birds to go around for 4-5 hunters as 8-10.
I will say this, I only ever waterfowl hunted a couple times again in Indiana after going up there, and that was for dark geese on private land. I did all my hunting for waterfowl in a week in ND/Canada and was more than satisfied. Piss on hoping to kill a duck or two (or even get a shot or two) on public land. That's IF you even get to hunt. I remember well driving to the local WMA at 3am hoping to get drawn for a blind…yes, they had daily draws for blinds.