I once used 1/2" drywall in a hallway that had a celing with 20" in between 2 joists. You wouldn't think it would matter but it while tapping I noticed it sagged at the edges. 3/8" I wouldn't even think would be up to code on a ceiling and probably would sag - also it does puncture more easily. 1/2" is whats recommended for 16" on center and would probably be sufficient. 5/8" is heavier but its also stiffer so if your using longer sheets its not shaped like a bow while your trying to screw it to the celing. I would use at least 1/2" and rent a drywall hoist. If if you have help its still worth it. Also stagger the seams - if you put all the butt end seams on the same joist it will probably crack on the seam.