My Trio Pro-Pilot for the G3X came with some makeshift brackets for mounting the pitch servo. Deffinately not as nice as they provided for the wing mount roll servo. These are a one size sort of fits all after some modifications with very few instructions type deal. Anyway I called trio and they were helpful giving me an idea how this should be installed.
I selected a location and fabricated the bracket that will support the pitch servo, just aft of the elevator bell crank. I deburred and dimpled the bracket, then primed and riveted it in place.
