Using the throttle strick to cut the engine is the method I've always used for my gassers. All it takes is simple adjustments of the throttle linkage and servo travel. You should be easily able to use the transmitter to bring the engine down to a low idle using the stick, then use the trim lever to fully close the carb butterfly from there. The only other "cut" option that I can think of that is just as effective is an optical kill switch. One that cuts the current to the ignition. The throttle method works just fine though.