You're right - crosshatching is equally spaced lines on the diagonal to create squares that are on point. Depending on how big your area is and how densely you want it quilted you can space them anywhere from 1/4" to 2" apart. Back in the day before long acrylic rulers were available we just used a yard stick, and the spacing was whatever the width of the stick was.
If the lines are perpendicular to each other you'll end up with squares, but if you change the angle you'll get diamonds. Here's a link for easy machine quilting http://dreamweavers-quilts.com/2009/10/easy-crosshatch-quilting/
I'm sorry there's such a delay in getting back to you! I didn't realize this was here, so I'm not sure if this is much help to you now.