Just a quick suggestion after having read previous posts about the pulley on the mainsail sheet being too high. When I built mine, I realised that the servo arm was much lower than the pulley and the sheet would enter the pulley at a very steep angle. (Asking for trouble IMHO)
My answer was to mount the pulley at 45 degrees on the bulkhead so that the sheet would enter the pulley at one angle and leave the pulley at another angle. That way, the sheet would form its own "straight line" and would not jam or leave the pulley. Simples.
Never had any problem with jamming or tangles.
Hope this helps.