With 5 chokes, one of them should accommodate both 00 ought buck and slugs to hold an effective pattern. As long as you and your partner aren't seperated while you're stalking by more the 7 to 10 yards.
BTW, both of you should practice as much with your sidearms as you do with the AR shotgun in case the man holding the shotgun is the one who gets attacked. (you just never know)