I don't know why you guys need to shut the engine off with the choke. I think a muck elegant idea is to cut the spark off. Look at the chain saws and weed eaters. That is the method they use. But what do I know? I am just a beginner in gas airplanes.
How do you do that from the transmitter? With a servo? An optical kill? It is an AMA requirement that you are able to kill any Gasoline engine from the transmitter. Manually grounding out the spark is not acceptable.