Use a reversible Y-harness with the Futaba 7-CAP . Believe me ,, it's better. You can't adjust elev trim equally while in flight with the 7-CAP. You do have aileron mixing that works perfect. But Futaba doesn't put in the correct elev mix features in radios less than the 9-C, etc.
And no,, I didn't post this because it's my thoughts or idea. Got it right from Futaba's website.