Its been well over a year since I’ve owned a glowforge and am yet to show any of my work. I wanted to dabble with mirrored Acrylic and alas I finally have. These are not proofgrade material except for one and were purchased at Inventables.
Materials used were red and light blue mirrored Acrylic, frosted white acrylic, and proofgrade medium draftboard for backing of skull flag.
The Yankees print was choppy around the edges but I added painters tape to reduce that choppiness on the rose.
Some of that edge choppiness looks flashback from the laser hitting the metal crumbtray. You can eliminate it by putting the acrylic on top of something else like plywood or cardboard (watch carefully for flare ups!) instead of directly on the tray.
I use a a simple sheet of paper - either copy paper or newspaper. It contains the flashback and is a cheap sacrificial material. It’s also thin enough that regardless of the thickness of your project material it won’t be thick enough to cause you an overall height issue with the GF’s 1/2" max.