[ngrubich]

Is the 4th leg level with the other 3, at least? If so, you could just add a shim where the gap is located. If not, can you disassemble that leg and rebuild it, or is it stuck where it is because of how everything else was built around it?

 

[ngrubich]

Let's not advocate using a drywall screw for anything but drywall. Way to brittle for a stand or any real woodworking. Better off with a regular wood screw or better yet a Spax

Mathias did an interesting set of experiments with drywall screws: http://woodgears.ca/joint_strength/drywall_screws.html

I'm not advocating one way or the other (I personally would rather stick with wood screws), just thought you would be interested in his findings ... although he is a little biased to drywall screws haha.