I think I am going to fashion a kill switch which is just a micro-switch driven by a wedge on the end of a nyrod control rod. Those electronic (opto-isolator) kill switches do not help the isolation challenge. Granted, the majority of the energy is electromagnetic propagation which can travel without a conductor, but anything to reduce the coupling is bound to help. I know my Tartan Twin is very noisy. So throttle and kill switch can both be nylon rods.