I take my bowhunting seriously, and figure a squirrel deserves just as good tackle as a deer. I use bodkin or ribtek heads for squirrel and a head I make by cutting a slot in standard blunts, and inserting the knockout from an electrical box(these are about the size of a quarter and easily file-shaped into a mini-broadhead) you then squeeze the blunt in a vise and put a touch of superglue on it. These would kill coon or coyote.
I do lose a lot of arrows stuck in trees, but when I hit a squirrel, it usually dies. I used to have them run off with blunts. They are hard to kill quickly, and I don't like to lose game.
I once shot through both lungs on a fox squirrel with a ribtek, and it ran down the tree, started up a den tree, and then fell dead. Probably 30 yard run with an inch hole in it!