Prairie Birds (Sharptail, Sage and Pheasant) I use RST # 7 in both barrels early season, late season switch to # 6 in left barrel.
Quail # 8 right barrel and 7 1/2 in left barrel.
Same combination in all gauge.

For Sharptails I use 6's because shots can be relatively long. I never use my 28 bore on them since I don't use anything larger than 7 1/2 in this gun. It doesn't handle 6's all that well. Because of the potential for longer range shots, I always considered sharptails and huns as 16 or 12 bore birds.

For ruffed grouse with the 28 bore, I use 3/4 oz loads of #9 early in the season and #8's later in the season. In my coverts, which are very thick even in the winter, long shots rarely occur and when they do, I don't shoot.

Ruffed grouse can be successfully hunted without a dog, but I would quit bird hunting if I didn't have a well trained (professionally) bird dog. It just wouldn't be the same for me without a canine companion.

Like Dean and Tom, for ruffed grouse I like smaller shot in the early season, especially in the right barrel, and 7 1/2s in the left. Later, I'll use 7 1/2s in both barrels. If I go after late January Iowa river bluff birds or Appalachian ruffs in February, I may slip a number 7 in the left barrel (and make sure it's copper plated). My go-to grouse 28s have open (right) and tight (left) chokes.

for grouse put me down as another 8's in the right and 7 1/2 in the left
(8's in both if its a woodcock spot that rarely shows me a grouse)

if and when I get a good second barrel shot at this mythical bird, I like the slight extra weight in the shot size because by then the bird is out there.

the season is rushing up on us. I just had the pup down in the Finger Lakes running him on a friend's quail - some nice points, still not completely steady to flush but he is not yet 9 month and had a late start with the hot summer. a crash course this next week - season starts a week from tomorrow - and the training grounds are on the way home from several of my covers - so tune ups are likely

the leaves are changing fast - told my daughter (aka training assistant) that I might not have to shoot as many of them down this year.

just waiting to see if the long dry spell will depopulate many of my woodcock spots - they are going to need diamond bits to get into some of this ground

I think the combination of 8's in the right barrel and 7 1/2's in the left is a sound choice for general ruffed grouse shooting, although I use 9's in both barrels. But it really comes down to the thickness of the cover and the average range of the shots. I hunt ruffed grouse in Sasketechawan incidental to my sharptail and hun shooting. The wooded cover surrounding the sharptail fields contains many grouse although you have to walk longer for a shot than you do in my home coverts in NY. They are not concentrated as the NY birds are. The shots are typically longer and I simply use my modified and full guns using my sharptail loads of 1200 fps and 1 1/4 oz. of #6 shot. It works well for me although if I was just hunting the ruffed grouse I would probably use 7 1/2's. It all depends on the cover and average distance the birds are taken.