This is a remix of a leather thickness gauge I found on another site. 

What I changed:

I reduced the height of the markings so they no longer stick up as far.

I changed the corners to give some relatively common corners in leather.

I think I made it more AMS friendly, but that is not required. It does help with contrast though. Both AMS and non-AMS are on the same plate.

I moved the hanging hole to top center while keeping the same size.

I tried to clean up the geometry.

Overall Measurements:

Length: 106.689 mm

Width: 50.794 mm

Thickness: 3.000 mm

Total Time: 1h12m on my stock A1 with AMS. 1h0m without AMS.