As everyone that has been in this position will tell you. PATTERN YOUR GUN. A full in mine might be a IC in yours. I personally use factory Benelli chokes, Briley and Trulock. I have patterned thousands of rounds in hundreds of guns and on average a LM, Mod or even an IM works for waterfowl FOR ME. Depending on range you can even use a IC or skeet. In my guns I get the 40 yd pattern I like with BC using a Trulock IM or a Briley "goose" but I like hunting with a tighter pattern than most and am known amongst the guys I hunt with as "long shot" but I can still easily take 20 yd birds with the IM.
Brand wise I would not own a patternmaster, IMO they are over priced and do not pattern as good as a briley or truLock in my testing. You can also try the Carlsons waterfowl pack (I have one for sale for Browning) that contains the close, mid and long range chokes in a nice plastic box. You can get a great choke for well under $50
Hit the range, Hang some paper and shoot,