VaWaterfowler, it is true that using a full choke is not generally needed for steel shot, but it can be used with smaller shot if the situation permits.

This post is talking about pass shooting, a form of waterfowl hunting that most people never take part in. He is probably hunting a place that the birds would never land in, but only pass over. If they pass low enough it can provide some good shooting. Unfortunately, many of the shots generally are at near max range and the birds are moving quickly. That is why you need heavy shot and tight chokes to take birds consistently while pass shooting.

just throwing in my 2 cents, but imo if you start thinking about how far to lead the shot its a mistake, the best way to shoot is by feel(instinct) if you think about the shot your brain gets in the way and you will miss alot. upland hunting is great practice ,dove season awesome if you can consistently down fast flying doves or quail and pheasant then ducks and geese will be no problem, but lacking those methods head on out to as skeet range, after shooting enough you will just naturally feel when to pull the trigger and i guarantee your sucess will be much better. Like anything else in life the more you do it the better you are.
Good Luck out there

buy you a dozen flambeuas or greenhead gear mallard dekes and set em out , cost less than 30 bucks , might invest in a inexpensive call like a haydels that come with an instructional cassete tape...A dozen dekes and just a little bit of chatter should at least get the ducks to do a closer flyby to inspect your dekes sittin out in that field...

Listen to Roadkill. Sound plan.

Best bet is to give up where you are at and get where the birds want to be. If not possible to decoy them, you are basically dove hunting. But you have got to pattern your chokes and get your timing down to hunt like that. You are missing all the fun of duck hunting if you have to shoot them like that. If that is your ONLY option, mail me and will have you pulling them out of the sky in no time. It is easy to bring them down at 60-65 yards if that is your only option. But you are really missing the real deal that way. Me and two of my buddies can sometimes bring down 7-8 greenheads in a single flock and never even wound a hen.