i actually work in situations where i need to maintain some sort of proficiency in h2h. i'd go with the winpipe blow as a first chop or punch. just make sure it's to the windpipe, and not the side of the neck. if this gets him bent over (or even if not) get around back and give a hellacious chop or stiff punch to the back of the neck, right at the base of the skull.
in some military h2h training i had, we were taught the double hammer fists to high up on the traps. they made us do this this to each other at real impact levels. even when they knew it was coming, half the motherfuckers went down.
this isn't a good first blow while facing off, though. too much telegraphing. when you do this, you wanna make sure that you're putting all you got into it.
then kick the motherfucker in the face.
this help?