Phasing the motors for a coax which uses two H3-120 swashplates

I am new to Ardupilot and this is my first post on this community.
I am building a Coaxcopter which uses two H3-120 Swashplates for each propellers and just two servos on each Swashplates. The rotor is fixed pitch and the drone utilizes the cyclic controls for pitch and roll, and motor speed variations for yaw control.
Something similar to the sprite vehicle discussed in this post here New Co-Axial Heli? - #9 by hybrid-guy

I am using a Pixhawk 6x flight controller with latest Ardupilot firmware.
So far i was trying to use a Tinsy 4.1 (running servo phasing code) connected to servo output of the Pixhawk but it doesn’t seem to work appropriately, therefore I would like to know how can I phase the servos in the Ardupilot to respond correctly for H3-120 Swashplates, I cant switch to a 90 degree Swashplate because of certain constraints.