I hunt with F/F and M/F for all upland birds. Never missed a bird because I had "too much choke". I did turn a mudbat into a gooey feather pillow once though.
I do make spreader loads for hunting in the 20, 16 and 12. They're good for mudbat and early season grouse for the right barrel. If we're into a mudbat flight I'll load a spreader in both barrels so I don't destroy the birds. I load the spreaders with 9, 10 or 11 shot.