I don't get to hunt grouse much in AZ, but I used to in PA. The chokes I use on my Parker 20ga, which is my favorite bird gun, is skeet and modified. Works well for desert quail, Huns in Idaho and even pheasant in South Dakota. If I were making the gun exclusively for grouse and skeet I would probably go with skeet1 and skeet 2 as I can not recall ever having a shot at grouse beyond 25yds.