Correct on the Y harness. You need to run ailerons on ch1 and 6 so you can mix spoilerons.

If you want the plane to do a tight waterfall or KE spin you need to mix up ailerons with up elevator and down with down. I turn the mix on anytime I want the plane to flip over itself like the waterfall or reduce wing rock in an elevator.

You can do the engine thrust later just don't CA those bolts on. The thrust line is trial and error. On a calm day, at about 3/4 throttle pull into a vertical climb. If the plane veers left shim the motor to the right (ie right thrust). If the plane pulls to the canopy turn the motor down (ie down thrust) I had to do both. Now my plane climbs vertical by itself. Much more fun to fly and makes me look much better

My engine points down 4 degrees relative to the horizontal stabilizer.

Keep us posted.