I think if you were to just slot the wood and slide the wood in (you know, to eliminate the seam) it could probably be reinforced with a pin of some sort to keep the key from wanting to pull out of the head since the 'type 1' design would be resistant to this due to the fitted slot.

Also, I might have to try this this weekend, I think we might have a chunk of cocobolo or ebony floating around somewhere that would work pretty well, and I have about 4 or 6 extra keys to mess around with lol

Edit-I'm sorry, pin through that hole in the metal part of the key head

__________________
1982 300D Turbodiesel, daily driver. Mods so far: Fram 8038 paper filter, 4 brake light mod, Gen II w126 (front) rotors/calipers, boost turned up to 12lbs, non-egr manifolds, water/methanol injection, 4-speed manual
1980 300SD Turbodiesel, project car, nearly ready to hit the street

1974 240D, New paint