If we go back to the original question, think about what is happening in your engine if at runaway revs you put on the choke to kill the engine, you flood the engine with fuel at best you have taken a few thou off the cylinder bore, at worst you have hydolocked the engine and bent the con rod, not saying that it always happen but it can, if you must have a Tx operated kill system doing it on the throttle trim is the first option, if you want more than that its up too you, fill your plane with as many redundent systems as you like it does not make any difference if you have confidence in what you are doing and you are conforming to the local by-laws and any air traffic navigation order in your area, just enjoy yourself and let others do the same.

Mike