help with rack-n-pinion setup

Being a NON engineer[read carpenter] I need some help calculating
torque to pinion for following:
Driving from both sides,probably 16pitch 2"dia pinion.
What I am moving is a gantry with total weight close to 500#
Using profile rails coE of .006.
Need to accelerate to 1500ipm @ 4ftpermin/min.Decel about the same.
best I can do is guess 250lbs needed,which means 4000ozin at shaft?
Is that enough info for one of the resident experts?

The resulting torque required will determine if I use steppers or
servos that I have on hand.
thanks
Carl