Take the cover off the servo controller. Remove the wire retaining clip.
Remove the cable from the servo hub.
pull the slack from the servo cable. Measure from the end of the cable sheath to the bottom of the cable end. (Don't remember the number off the top of my head). Make your adjustments with the threaded adjuster in the cable about 6" from the end of the cable.
Just make sure they are the same length and that you have the slack out of the cable when you measure.
Thunder
Here is an the way to measure the lenght. Don't trust the numbers they are for my M1000. Again it is in your manual what you should have.