I asked John about the prop size this morning. He said he would measure it but doesn't remember its size off-hand. He replaced it with a larger prop because of the engine replacement and made the prop aperture larger when he built the new rudder.

The thru-hulls are for exhaust and for bilge pumps. The larger is attached to a Whale Gusher pump operated from the cockpit. The small nipple John said he "left in" to be attached to an electric bilge pump. I assume that it was there to serve that punction in the original design.