The screw post nicking the wire would be an easy fix, but I can see a fixed toothless clip working better if mounted properly so holds up, or can be easily replaced. ya dude, take it from me, those dimensions are pretty tight for what would have to go in there.
There is a link somewhere in the thread...I have bookmarked at work and can add it tomorrow. The box is modeled as a 2"x4"x1" project box, but I'm not 100% sure everything will fit. Also breaktru made a good point cautioning against using the screw post as it might nick the wire and damage it. I will probably just use a fixed brass alligator clip instead.