Z Axis cal Jig for I3 Mega

I could not fine a good way to measure accurately, and repeatable, the Z axis to set up both micro switches. I made this, I took the average distance between the X and Y 8 mm bars as my printer came, for me it was 64 mm when "home all" was done.
To use first clean up the print, then snap the wide end on the Y rail and rotate onto the X rail (with motor's turned off) adjust the Z screws by hand so the X rail just rests in the cup, with out bending or warping anything. Then adjust the long Phili