rctom,
I was not referring to your pic when I made my comments, I have seen this type of install in other planes. Look at the attached pic. All I'm saying is that from what I've read this type of install is a not recommended. Roger can probably give a better explanation than I can but I was always under the impression that radio components(servo's,batteries..etc) were to be kept away from the ignition system. Notice in the pic that the engine is soft mounted, RC Showcase does not recommend soft mounting ZDZ engines. But the gentleman who installed this engine did so, I guess for him that was the right way to do it. It's your plane and you can do what you want.
Diablo maybe holding power was not the correct term. The butterfly on my ZDZ turns rather easily, what I wanted to avoid was using a servo that could not hold the throttle position or wandered. Correct me if I am wrong but I thought that when doing 3D maneuvers, such as torque rolls, throttle management and precise throttle control were important. I just didn't feel that I could get this with a standard torque servo and the throttle on my ZDZ. This is just my opinion and I may be wrong.