A couple late thoughts from left field. Check out the Walboro web site so that you under stand how a Walboro works. Make a large two needle R/C model carb, get a repair kit for and large Walboro and use the parts to make a regulator. Use crankcase pressure to move fuel from the tank to the regulator.
If your engine MUST run CW then using a production pusher prop mounted on the front will work. Of course you will need left thrust built into the firewall.