I also posted this in the Photos section, and received a comment from one of the guys who had a somewhat similar store bought mount. He had problems with squirrels sitting on the camera, and their weight would cause it to tilt toward the ground.
If you have that concern (or a heavy camera), replace the thumb screw and wing nut that hold the screw eye in place with a regular hex bolt and hex nut. Then use two small wrenches to really crank it down tight.
That might be a better way to go anyway. You'd just have to remember to stick the wrenches in your pocket.