I habitually use 8's for Grouse esp in the right barrel as the season wears on the left tube will get 7's or 71/2. I almost never use a load heavier than 7/8oz in both the 16's and 20's the 28's are obviously less and while I'm no fan of a 12, a Purdey light game gun caught my attention a while back. It's a tad over 6lbs and the 27 inch barrels are choked .004 and .008 and it's just about perfect. The only shells iv'e used are RST 2" paper and 3/4oz of 7's or 8's.
A good dog can make a bad shot become a great one. I have had the dog retrieve grouse and pheasants that I didn't think were hit or not hit hard enough and would have been lost to coyote bait. IMHO bird hunting with out a dog is just a walk in the woods with a gun.
Grouse season is a short ten months away. It will be a special October as it will be Ike's first full year in the uplands. I'm thinking he will need a gun in his honor and it should be a 16 with 26 inch barrels and open chokes
Ted RST makes a shell with #10 shot. They worked fine on woodcock and quail but hunting in the thick cover of the Upper Peninsula and never knowing what's at the end of a point be it grouse or woodcock I lean towards a larger shot size.