So I stopped by the hardware store last weekend, interested in picking up some glass to experiment with for a print platform (It looks like the laser-cut plywood might be starting to warp, I live in a humid place). They guys there were nice enough to just cut me a 6" x 6" piece of scrap window glass for free, since I'd have to pay for the whole sheet (24" x 24") otherwise.
After three generations of so-so results (lots of slippage, and they tended to reduce my X-Axis travel by getting in the way), I've settled on this to mount it. It also uses some of those little Goody brand rubber bands to keep tension, something like $2 at the grocery store, some springs I found at Home Depot (8mm ID / 20mm Uncompressed Length), and some #4 nuts and bolts.
Printing directly on to the glass has had mixed results. Since I don't have a heater, I've tried both with and without PLA "Juice", bare glass, and on painters tape.
Printing on bare glass makes for beautiful print surface results. The bottoms come out looking like a mirror. The problem is the parts don't stick very well. Tried smooshing the bottom layer, still dislodges whenever there is too much sideways force.
With the PLA Juice (elmers glue + water), it printed okay. I still had issues with sticking on longer prints. I heard I'm supposed to use PLAc glue, but I have no idea what that is. Might try it next time I stop by the hardware store.
I'm currently running with the blue tape, so this gives it a little extra bite around the corners.
In the end, I got a super-flat build platform that is way easier to clean and retape compared to the plywood. I also don't have to worry about the warping issue I had before, though with the added X-Y tension, it may migrate down the to X Carriage.