I am an Opti Kill user too. I have them on every one of my planes.
I use the monetary switch on my radio for the kill switch and I will tell you why. I accidentally hit the kill switch on my radio one day and I couldn't get my finger back to the switch fast enough. I ended up sticking my Sukhoi in the top of a three.
Now that I use the monetary, if I hit that switch it snaps back on and the engine catches back up.