I'm having trouble calculating the right steps/AppUnit for the servo motors im using...

Can anyone demonstrate how to calculate the correct settings so the motors move the correct distance ?

my setup consists of the following:

· ADTECH servos - http://www.adtechen.com/products/ACH-09075BC%28750W%29-Middle-Inertia-Servo-Motor.html

· 3.2:1 belt reduction - CNCRouterparts pro rack and pinion drive - http://www.cncrouterparts.com/pro-rack-and-pinion-drive-nema-34-p-226.html

· 35 Tooth Pinion and MOD1 Rack

any help would be very much appreciated