Gene, you have th old style ignition with only the two wires from what I can see. The new ignition has the plug wire plus three. I'm sure by now you have noticed that. I set mine up like Ken, a regular JR switch on the outside of the plane plus a second way to kill the engine with the radio. The optical kill switch is the new kid on the block and all the rage but I have done it with a servo activated kill switch or just a choke servo, they all work but the optical is also the easy way. By the way, the DLE 55 is really an outstanding engine.
Gene