modified CNC router table for woodturning lathe

I am designing a CNC 2 axis router table to mount to a large
woodturning lathe. It will allow roughing out shapes on the lathe
such as large vases and bowls. It will also allow barley twists and
rope designs to be cut on curved surfaces. My original version was a
manual one using a rack and gear.

I plan to use a 5 tpi acme thread leadscrew on both axes. The basic
design will use round rails. Travel is 8 feet x 1.5 feet. Also
plan stepper motors.

My question first today is about using a leadscrew and minimizing
backlash. Can two simple acme nuts be placed on each side of the
carriage and adjusted against the opposite shoulders of the thread
to minimize backlash? or do I need to purchase some type of special
antibacklash nut?

Second question is whether I should drive the screws directly with
the steppers or use timing belts and pulleys.

Thanks,

Keith Clark