It's a good idea, but I hope he tries to come up with a blunt-wedge version, since, it seems to me, that for us arbos, the turn wedge really only has an advantage over conventional wedges in topping situations; and that only because it enables you to wedge a tree without a heavy pounder. Blunt wedges are a must for arbos who don't always have the luxury of guys on a pull-line, cause the wood we are dealing with is extremely small, even though (here in the Northwest) we might be dealing with fifty or sixty feet of top. Most of the arbs that I know who have tried to wedge tops have all--at least at one time--wedged their saw into the tree.
My latest idea: No face cut!! Just a back-cut backed up by a blunt wedge, and then just start rocking your body-weight back and forth on that pig while you palm the wedge in deeper on the forward thrust, or hammer it in with the but end of another wedge. Haven't really tried it yet though, but I just drilled holes through the thin ends of four wedges of various taper so that a "William" carabiner can fit through em'. Next time I'm not gonna smash a house, I'm gonna give it a go.