I do not understand your post very well.
The Futaba GY190 should be put in between the RX and the nose wheel servo.
It will track your plane straight during take-off, and has even more advantage when you apply wheel brakes (unvoluntary differential in braking between left and right wheel would cause your plane to turn)

The manual can be found on the Futaba website : http://manuals.hobbico.com/fut/g190-manual.pdf

Nicolas.