Please post a recipe for said gravy
Not sure if you were asking me, but I find that the best gravy for squirrels is just what comes from the squirrels mixed with water. Once you've got the squirrels cooked and tender, take them out, add some flour to the gravy in the pot to thicken it up, and then put the squirrels back in.
Of course, this method depends a lot on how you seasoned the squirrels. I use my grandpa's seasoning (think less salty than Tony's and less red pepper than Slap Ya Mama), and it works like a charm.