you’ll be fine. because I was poor and lazy, my clamp eventually just rusted in place, lol. it wasn’t really a display, so i didn’t care about how ghetto it looked but it worked. i’d leave that clamped for a good 4-5 days. there are plenty of online sources of guidance for how long acrylic needs to fully cure given joint thickness, etc....but it’s at least days and maybe a week or so for a full cure. also, with the clamp there you don’t even need to have the tank drained halfway - good luck and keep us posted