I wear TONS of plaid as a camo pattern. That said, I have experimented quite a bit with grey wool......note I said WOOL. You don't get the same effect from something without depth of fiber, like cotton.
If I could choose only one pattern/color, for the rest of my hunts, be they winter, spring, or fall, it would be GREY WOOL.
To my eye, and to my cameras lens....grey wool blends as well as anything available. Look at deer in winter....grey. Timber wolves...grey. Coyotes....grey. Rabbits...grey.