Why would you want to offset the thrust angle of the engine? Other than some Jets, can you name a full scale plane that does it? I know that some like it so they can more easily hold an up-line, or not have the plane wander when doing a loop, but is that not what the rudder is for? Same with down thrust, sounds like too much throttle or the wrong incidence to me. if you have a problem with the model balooning under throttle, why not back off the throttle a little? I stopped using thrust differential quite a while ago, and have become a better pilot for it. Just my 2 cents worth.

Bill, AMA 4720
WACO Brotherhood #1