Got the exact-cut plexi in place. Looks out standing over the bezel--
One thing about the Happ 19" bezel (or maybe a couple of things):
Although it's 25x25 and my opening in the UAII kit is 27x25, it was still a tiny bit tall--probably an issue with the kit, but nothing major. I used a grinder to slice off about 1/8" off the top and then I used my plexi glass scoring tool to score the inside of the bezel--just to make it fit my 21" monitor.
That worked out like a dream for trimming it and then went over my imperfections with the grinder again, just for a better look.
After that, I'm about an inch short on width, so I've purchased weather stripping and I'm using double-sided tape to stick it to the sides of the cabinet (there's wooden pieces that are sort of "stoppers" to catch your bezel/plexi) and they seal off the rest of the light that was coming through.
Looks great, works great, plays great!