I have the same shotgun and I use a choke that is rated at full steel/mod lead for pass shooting geese with 3" or 3 1/2"BB or BBB steel. When shooting duck over decoys I switch to the Remchoke Imp Cyl choke and use #4 steel.
I've seen guys using chokes labed full and even xfull (lead) but I wouldn't recommend it. That's a lot of restriction and just setting yourself up for a potential hazard.