AHK is pretty painful to do anything, much less something this complex. 🙂
1) It would be simple to remove the other Clippy features (though they are awesome). All features can be disabled thru configuration except the clipboard history (which is fantastic). Else, to setup a dev environment, download Clippy’s source, download Eclipse, click import existing project. It’s easy.
2) The SDK is supposed to work with the EyeX, so Clippy should too.
3) If head tracking is more accurate, then that would be nice, but otherwise tracking the eye location works just fine.
Since eye tracking is not accurate enough, it still comes down to hold a button, make sure the mouse is in the right place, let go of the button. This takes away a LOT of the magic when eye tracking is accurate, which feels like your are controlling the computer with your brain. Still, it’s pretty good and does reduce the need to grab the mouse.