Id do glass. Sturdy, easy to clean and you can cut on it.
I agree. On smaller sized light tables, glass is nice. Consider backspraying the glass with translucent white paint or laminate the back side with translucent vinyl. This keeps you from staring at the light source, which used to give me headaches.
I worked at a shop for a couple years that did backlit awnings and canopies almost exclusively. Our two main work tables were 6x90 feet long in 10-foot sections on casters. Built in to each work table was its own pair of 4-1/2x10 light table sections, which could be inserted at any point along the 90-foot lengths. We used the light table sections almost daily for registering and laying translucent colors for various logos.
The lighted sections had polycarbonate tops, a double layer of 3/16" clear, with fluorescent HO lamps about 12 inches below the tops. There was a row of upright dowels supporting the middles to minimize the sag of the plastic.
These lighted sections probably saved hundreds of labor hours a year. Vinyl colors had to be laid very wet with no accelerant (like Rapid Tac). Even then, the heat from the HO lamps dried the moisture quickly, so the vinyl had to be laid and squeegeed rapidly.
This was the only place I ever worked at that used light tables for high production. I don't think they could have met their deadlines without them.
Since working there, I have lobbied for light tables everywhere I've worked.
This company made backlit fascias for the canopies that serve as the roofs for the gas pump areas at truck stops. Some of these fascias were over 100 feet long, with lots of eradication work and sometimes multiple layers of translucent vinyl.
A crew of seven could produce a complete set of canopy fascias, plus a backlit fascia for the front of the building,
and a 30-foot waterfall awning for the restaurant, for a TA Truck Stop in four ten-hour days, leaving Friday for crating and shipping.
It was exhausting and fun. And I don't ever want to do it again.
Brad in Kansas City