Tail was changed due to T-tail being not effective.
DIFFERENT APPROACH FOR GETTING DIFFERENTIAL THRUST
Don't have an extra channel? Don't know how to program a mix? Purchase a GWS "V-Tail mixer" at a LHS or order it. Notice it says "aile" in upper left and "elev" in lower left.
How it works.
Since elevator(s) go up or down in the same direction, that is what makes your 2 motors run together. So that lead that goes in THROTTLE channel.
Ailerons have opposite direction, so you want one motor to increase and the other to decrease, now the other lead goes in RUDDER channel.
Now connect(50-50 chance") the two ESC'S from left and right motors(no props please) apply power, and move throttle up and both motors should run togeather. If not, reverse ESC leads. Then try rudder, you will see one motor increase and the other decrease.
Then go to TX rudder and adjust rate and expo for range of differential. Fly and adjust to suit your flying.
By changing trims for both rudder and throttle, it will allow you to start both engines together and while in flight, allows you to sync the props. That is one cool sound to have.
Note, each motor has different internal resistance and no 2 motors will start or sync at the same time.