Step 1: Get a CAD program
Step 2: Model a rectangle that is bigger than 11 mm x 8 mm
Step 3: Model a smaller rectangle within that rectangle that is 7.5 mm x 5.5 mm
Step 4: Make holes at the corner of the smaller rectangle that is at least 1.575 mm in diameter
Step 5: Extrude and copy these squares and you should have risers ready to print
Step 6: Save as an STL, throw it in your favorite splicing program and 3d print

OR

Just download and print this
https://www.thingiverse.com/thing:3104358/files

:/