I finished precutting all the sheets earlier this week after work (thanks to whoever it was who posted the link to CutList
btw, invaluable). Cut the driver hole (used jigsaw and then wood file to clean it up; followed by and angled router bit to give some relief on one side for the driver surround to clear), got the hurricane nuts set, and installed panel 1 on Thursday. Then went at it and made good progress yesterday after work (thankfully I telecommute on Fridays, so as soon as I ended work, I went at it and got in about four hours).
The plywood in the background is for something else - nicely warped 1/4" plywood. Actually one of the sheets I used for the THT was pretty warped too, hence the pipe clamps straightening it out.
I got a little overzealous trying to compensate for the warped panel, and was working a bit too fast, and ended up shoving the 2/8 braces in a bit too far / hard, resulting in a somewhat pregnant bulge on one side. On the left side you can see the panel curving out a bit, I think it won't be too bad once I mount the last panel and pull it in before screwing it down.
CutList printout in the background, and some more braces marked and clamped, ready to work some more today after I get back from my son's soccer game, and from the supermarket (having people over tonight, need to get cooking stuff - going to make some crockpot pulled pork and some seasoned fries and onion rings). The pile of panels and braces is getting significantly smaller, yay!
Looks like I have some scraping to do to cleanup the extra PL. I don't know why people make such a big deal out of the messiness of PL, I didn't find it that hard to get off my hands with soap and water.
Hitting 1/2" plywood on edge with a screw is kind of hit and miss - here are a couple of the misses.
Thanks for the feedback on finishes. I'll look for something cheap, Duratex seems pretty pricey, maybe I'll just get a can of primer and black latex paint at Home Depot. I wonder if a quart or would be enough, or if I should just get a gallon.