I have a Remington 870 express super magnum 12 gauge 3 1/2" that has a modified choke and im not sure if that is a good choke to use for duck hunting. Most of my hunting consists of big game and varmints so I don't have a lot of experience with waterfowl. I will mainly use this gun for ducks and will be shooting Winchester xpert hi velocity steel shot #2. Thanks for the help