RE: Lengthen the Y harness
here's what I would do (And have done many times)
Lengthen the SERVO wires instead of the Y cord (Using the soldering method). Make them long enough to go completely through the wing and easily reach the Y cord. That way, you can always use them without the Y cord if you ever want to plug into 2 separate channels, or if you want to install them in the tail of an airplane.