My pleasure, Oren, Ed, and CRNG.

A bit mo The original mirror had roughly 4 feet x 2-inch trim pieces, one on each vertical side of the mirror, attached with double-sided tape. The trim's long edges are beautifully beveled. Today I marked the new length of the trim that I wanted with a sharpie marker; put on safety glasses, thick gloves, and a breathing mask; and etched the trim using a 3/4-inch diameter diamond rotary cutting disc. The disc was mounted on my ordinary Black and Decker electric hand drill using the mandrel that came with the discs. I bought these little discs at Harbor Freight some years ago for a metal project. See https://www.harborfreight.com/diamon...-pc-69657.html . The discs were not helpful for the metal project. They were great for cutting these mirror trim pieces.

I put the trim on the sharp edge of a work table, tapped on the back a little with an ordinary hammer, flipped the trim, and easily snapped it to the marked length. I sanded the cuts a bit with 100-grit sandpaper. After some practice with scraps, the last cut I did is so good it is hard to tell the difference between it and the professionally done ends.