I think you have to remember that the aileron and elevator servos in your illustration have to work together just like MvR's arm would have. There is no movement separation. If the ailerons are moved there will be a small amount of elevator movement, (use ball links to minimize slop and misalignment), that the pilot will compensate for. I find that, while there may be other ways, (and reasons), to route control runs, following the original seems to always work.

Martin