Newbie questions: Enco milling table conversion?

Hi everyone,
I recently acquired an Enco drill/mill table at a great price from a
friend. It is the one with the 11" x 7.5" travel. I plan on
converting it for use with stepper so that I can perform some simple
relief carving.

Now for the question: Is there a rule of thumb for calculating the
gear reduction that I will need in order to reliably use steppers
with this table? I currently have some Vexta unipolar motors that
are rated at 125 oz-in holding force. I just need to figure out the
reduction I will need before I (a) have my friend turn a set of
pulleys or (b) order a set of gears.

Has anyone done this conversion? The slides have quite a bit of
resistance, and I have a bad feeling that I won't be able to use my
steppers...

Thanks for any help!

Bill Byler