I don't see why you are thinking of getting an after market choke. The ones that came with your shotgun were built for that shotgun. Read on your full choke to see if it says..."Not to be used with steel shot". I got a new Benelli Nova this year and I can't use my full choke with steel. Too bad, cuz I love that tight pattern.
I haven't even tried to shoot anything with it yet. I am however going out tomorrow afternoon to get some geese. I did my scouting today, and the shotgun is already beside the front door.
If you think you're addicted to duck hunting, wait 'til you learn to hunt geese. There's no turning back!
Good luck.

critch