Thanks for the replies. This project is the unfinished basement where I live, but it's not my place. I'm doing the drywall in exchange for 2 months free rent. (It works out about 15% less than I would normally charge, but I don't have any travel expenses.)
The framing is BAD. Last night I hung a 16 foot board with a cutout for the bathroom where the angle of the cutout lost a half inch per foot (2 inches out of square over just more than 4 feet). The first several boards I cut thinking they were at least close to square. With plumbing box cutouts (which themselves looked like Mad Hatter contraptions before I shimmed them out to plumb, level, and square) already cut out and the board already on the hoist I just had to pick which end of which side of the board would get a big gap. Another wall he built around the laundry was attached to the ceiling and the next wall, but not the floor/foundation. It allowed at least 6 inches of swing. I pulled out my rafter square and fixed it. Unfortunately all the others that have been off were attached very solidly to the floor. I have to give him credit for that. He is not planning on anything moving.
Anyway, it's been quite a project. Normally I wouldn't bother fixing all of this, but since I'm going to be seeing it every day I decided it's worth the extra effort.
The owner showed up yesterday to do the tile before I saw the replies here. I asked him how he wanted the corners. He said there's no need to tape the lids, and just throw a corner bead on the one I showed you and he would finish it off. So I did.
Thanks again for the replies. I learned for future reference anyway.
