With 3.5 in shells you could use 2,4, or 6's. I usually like 2&4's to give me more range. As far as chokes, i prefer full, again gives me increased accuracy at futhur ranges. I've been shooting since i was 5 and shoot competitively and use a full choke for that, so for me a full choke is better. If you dont feel very accurate i'd go will mod. or improved cyl. Factory chokes are fine. If you want to get an after market go w/ a Pattern Master. Best ive found for geese and ducks. As far as your plan to get the geese, get there before they do, try to get some good concealent and make sure your firing in a safe direction. We have geese on our farm, if they dont stay over night they usually come in a little after sunrise.