Regarding a batch of bird shot, I can't imagine that working. I've patterned bird shot, and there is likely to be good chance of missing the eyes. I've used skeet loads on dragon flies, just for fun, and if I can't pop a 4" dragon fly at 30 feet I'm sure as hell not going to hit the eyes of a charging bear. Being as bears have been known to tear open bee hives, I doubt that a load of #7s will chase them back. Failing to blind it, I'm really not sure what good it will do to fire bird shot at something that is big enough to stomp the crap out of other grizzlies for breeding rights. Even right on skin contact will not give the sort of damaging penetration that you need to stop it's heart before it swallows your head.
Not that I really care too much what a person uses in pursuit of his own safety, that is his choice, but this is the one thing suggested so far that seems to have absolutely no merit at all, and I'd hate to think that someone walks away from here believing that a montana pheasant hunter is safe from grizzly because of his shotgun full of #4 or 6.