need help in motor calibration

I have the following information that I need help in:

Driver: Gecko G210 set to 10 microsteps.

Motors: Stepper motors of www.nanotec.com:

Current per winding: 4.0 Amp (P)
Holding Torque: 1321 oz/in (933 Ncm)
Resistance per Winding(Ohm):1.94
Inductance per Winding (mH): 22
Rotor Inertia(gcm2):4000
1.8 Degrees

mechanical: Gantry xyz rack and pinion direct drive:
Pinion size (dia) without teeth: 36mm
pitch: 1.5mm
Pinion teeth: 24

Q1.can you help me figure out the speed?

I got the help of figuring out the following calculations from
user:rszemeti @ Geckodrive group

Thank you rszemeti

I have 24 teeth per rev @ 1.5mm per tooth = 36mm of movement per
rev.

the motors are 200 steps per rev (360/1.8) .. so the movement per
*whole* step is 36mm/200 0.18mm, I am using 10:1 microstepping so
0.18/10 = 0.018mm per rev or 1 / 0.018mm =55.55555(recurring)
steps per mm = 55.55555 * 25.4 = 1411.111097 per inch

Now...on mach2 config>motor tuning I get to a screen with the
following title "motor setup velocity/acceleration"

I have numbers to fill in :

Velocity:!
Acceleration:!
steps per unit: ( I entered 1411.111097 for inch = 55.555555 * 25.4)
however its not working
Minimum pulse width= !
Direction precharge= !

What I get for the number I have entered (1411.111) is if I am
calculating a 20" of movement of a single x-axis I get a 50+ actual
movement

Please help me understand how to work it out and solve the problem.