Building a new tricopter flying wing tiltrotor with 3 motors tilting... need some guidance please

Been working on a flying wing tricopter for a while now using QGC and had no luck getting what I need. I saw a person in China make what I needed using Arduplane and I am hoping to make my plane work.
https://www.youtube.com/watch?v=WMh8BiOLrns

I have a 2 meter, carbon fiber flying wing with 3 motors. Currently the front 2 motors tilt and act as yaw control (derived from the “convergence” firmware used in QGC).
But, I want the aft motor to tilt fore & aft for position and thrust control. It makes the plane perform much better in wind.

I have some questions about the Q Frame setup… I have my frame as as a tri (#7) but my motor configuration parameter does not have a specific “Tricopter” setup… only “V” and “Y6”. I have currently selected “v” but it seems to be assigning too many motors.

Any help would greatly appreciated

Thanks
Jeff

Bump - any ideas?

thanks

Jeff