RE: G20 Engine
The electrical hookup looks ok. The only thing that doesn't show up in diagrams is that I beleive that you need to have a metalic surface on your firewall. Something like copper or aluminum foil epoxied to the front. Also you don't want a metal clevis or pushrod going to the throttle. Last point I beleive the fiberoptic sender goes in the fuselage with the receiver, and the kill switch goes in front of the firewall with the engine ignition battery and ignition.
One last thing, you didn't mention what radio you are using. 2.4Ghz are not as sensitive as the 72Mhz systems for interference from the engine.