I agree with Danger and Russ you are complicating matters it does a loop because there is a person on the ground iterfering with its flight path. Any plane will only fly straight & level with a certain trim at a certain speed. To keep it level at a higer speed more down trim needs to be applied...
As far as I know the whole secret of side draught carbs are in the fact that they have very short intake manifolds producing power from a very low rpm. range. part of the m3 power is the 6 individual throttle bodies mounted directly on to the engine. Suggest you make the runners as short as...