I just posted the same question a few threads down in this forum. I have the same plane, but I am using 5645's, futaba PCM receiver, and a futaba 9C. I decided to go with a "y" harness and had one of the servos reversed using a programmer. It works fine and both halves move perfectly together. As long as one servo is reversed, the digital trim on your radio will work fine and they will both go in the same direction when changing the trim.

I initially tried programming them on separate channels, but I just could not get them to move together good enough for my taste.