You're right. SAme problem with 662. I'm going to do a Y-harness with a reverser. This is the first time I have had to do dual servos with a reverser. The plane is not for me and I'm sure the person would have a hard time with the trim if it needs to be changed.

The manual does talk about making the mix, easy to do. It doesn't state how to get rid of the other channels input and that was the frustrating part. I also wish the manual clearly stated how to change modulation. If you do it per the instructions you can't.