I am a newbie, don't believe me much, but I have crashed so many times replacing tail boom and having to move the servo. What I do to set it up fast is to play with the servo mounting in the tail boom, I don't move anything from the Tx, I leave SUBTRIM 0, Endpoints 100,100, and I initialize the servo to see where the center position of the servo is, I put the ball linkage to the hole that is in the certer position and I move the servo mounting forward, backwards until the tail pitch is in the middle of the tail shaft, then I screw the servo mounting and if there is some bindind, there will be on both sides (because the pitch is in the middle), if so, I just reduce the LIMITS of the GYRO (GY401) in the gyro and that is it, It has always worked for me.