it is 1/2 inch //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif
it was the only material they had ta the hardware store (small town). So we made due, as for the curve, I know that we should have all of the cuts touching eachother, but with such a slow curve at the bottom of the box it would have gotten pretty choppy. So we used a sub-flooring adhesive to go throughout. It hardened it up pretty good, and is a lot cheaper than resin. And I can't really see there being a problem with strength as my friend usually keeps the sub volume minimal anyways. I gotta get some install pictures yet, it was too dark out when we finished.