Integrated slider pad for Gorilla Rack

I have several Gorilla Racks in my garage that I wanted to slide, but they won't budge without assistance from furniture sliders. My two gripes about furniture sliders is that 1) they are expensive at $10 for a set of four, and 2) you can't butt two racks up against each other because even the smallest pads are too large.

I decided to try to print something that would give the corners of the racks a little more surface area, be easy to install, and also enable me to put racks next to each other.