Work on these has slowed considerably, but I've managed to make some solid progress. I flush trimmed all sides, then glued up the top and bottom panels. I've read threads recently on various forums bashing PL Premium for not curing (some have made a big deal after only 12 hours). I've never had a problem with it, but during this last use I definitely experienced the claims. The difference is, I know my tube was good so I gave it time, 3 days to be exact for it to fully cure. The temp had dropped significantly, and the humidity with it, so that's what I blame this whole fiasco on. Verdict is, dont rush with PL. After that cured I decided to add some bracing, which honestly isnt even need considering the box size and 3/4" ply.
I've got the front to back brace tied into the port with a line of PL, and there's another brace under the port tying into the bottom. I have a 45 degree angle brace I'll be adding to the top. I've really got to start thinking about bracing before I glue up the sides... Definitely getting extensive with the bracing on the center channel I'm doing next.