Securely mount your 5mm cell cast acrylic and use your bit of choice to cut. I prefer a single flute spiral upcut bit, at 75 ipm and a 0.04 depth per pass at 17,000 RPM. You can make heavier passes if the mounting is strong enough. I recommend using a spray bottle with water to cool the bit while it cuts, acrylic has a very narrow range between milling and melting, you need to move fast and cut at the right speed to keep the bit cool.
The mounting strip needs the bolt holes drilled out, I left them out so you can choose your own mounting height or you can even just mill a slot. The brushes need to be cut to length and epoxied in place, I recommend a dab of superglue to hold them in place while the epoxy sets. Mark the location of your bolt holes and drill them out, and epoxy the strip into the boot.