I have too agree with jetmech on this one. Half throttle is where you fly most of the time and in flight you want too stay level except you are doing a manuever, landing or on take off.

But I do have a question though - not all engines are the same - wouldn't you be flying some engine-plane combos at different throttle? For example - if you fly normally in a circuit for instance - you would have your throttle just under half since that then reaches the speed of the smaller engine planes. I don't know it's just something which occured to me now. Would you then trim it for that throttle setting?

Basically you trim your plane for level flight on the throttle setting you will fly the most?