Converting an ARF trainer into a scale model, is not a practical idea. Neither are your reasons for wanting high torque servos, where they are not required.

The model can be made to look sort of scale, by converting it to a tail dragger, and giving it a "scale" covering job.

The Tower Trainer requires standard servos. Put in a high torque for the rudder, if it makes you feel better.

Servo bays will need to be created for the ailerons. A single servo will not work, if you want flaperons.