Determining CL to make motor mounts for CNC mill conversion?

Hi all.

I want to convert my G1007 Grizzly mill to CNC.
I bought stepper motors and gears, but I'm not sure about a couple
things:

1. Easiest way to determine the bracket (shaft-to-shaft) centerline
so I can use a standard toothed belt length?

2. Where to get said belts and gears? (I got little gates belts with
the 1:3 gear sets I have that came with the motor)

Thanx.

(plz email me direct @ dspinnett@...)