I went through the trouble of creating a stencil. It may not be 100% accurate, but you can print it at a larger scale to have more coverage if you wish.
The 3m tape that came with my rack were too small...exposing part of the paint to the rubber pads. I just traced out the bottom of the pads onto a piece of paper and cut that out to use as a stencil. Traced it out onto some ppf and cut it a few mm larger. Super easy to do.