Microflight,
My theory does not apply to right thrust as you have removed the lifting area from the equation, the engine will try to pull to the right countering the torque of the engine, but there is not a wing pulling the other way.

Taildragger,
I agree that you climb with power, and you control airspeed with the elevator, anyone with a pilots licence can tell you that.

Thats what I base my oppinion on, When you add power you are causing the thrust of the airplane to increase the angle of attack of the wing, causing it to climb. If you only have 0' to 2' of downthrust this will not happen, as you increase power you will just increase speed with minor other effects I bet if you look at this trainer it has about 6' of downthrust already. I think 2' is the max you should go.

Just my humble opinion.

And I have read all of my flight training manuals