This is designed to hold an 8 1/2" piece of 1/4" glass in place on top of a Helios Heated Bed (from Panucatt) to get rid of the office clips that take space away from the build platform. It also gets rid of the springs under the bed that can cause some Y-Axis wiggle.
I have a newer version of this thing here: http://www.thingiverse.com/thing:71243
1) Measure the distance from your mount plate to your Helios bed.
2) Adjust the height of the lower portion of each corner to match your setup.
3) Print, install and check level.
4) Adjust and reprint needed corners or shim as required.
You'll notice back right and front left are the same so you can print one of each or 2 of one. The thickness is different in the all-inclusive "Corners.stl" because on my setup my X+ needed thicker bases for leveling (to give an example of how I did mine).