The easiest way to ensure your mirror blades don't get scratched is to fit them after the playfield is down and secure them will thin double sided Velcro.
You can then take them off very easily before lifting the playfield.
Also, not every machine/playfield scratches the mirror blades.
Some machines incl some new machines don't scratch them at all. It's luck of the draw and cabinets being made of wood, not every cabinet is exact or a tight fit.
I had an idea for for a cheap topper mod that I reckon would look great and reflect and look good with playfield lighting and backbox lighting bouncing off it. Chrome checker plate laser cut into the KISS letters.
That stuff is cheap , easy to laser cut but shiny chrome. Might end up being a $80 or $120 topper. Easy to put a few spots or flashers facing it, coloured or white.
Hoping Swinksy does something on his computer like that. If anyone knows how to laser cut and engineer something like that, Swinksy would easily.