The calibration adjusts for lens imperfections in the camera, it really has nothing to do with the monitor. (I'm assuming that Pointable doesn't have its own "calibration" -- I haven't used it since I'm a Mac user primarily.)
As for jittery tracking, look at your frame rate in the Leap Motion Visualizer (with both hands in view). It should be around 100fps. If it is much lower, tracking can suffer. Also the larger the screen area that the cursor is mapped to, the more any hand tremor and tracking instability is magnified -- that could explain some of the difference between your experience with the app and the demo videos.
As for UV lights, those aren't a problem per se. The cameras us IR light on the opposite end of the visible spectrum. IR reflections off metallic parts of the lights (or ducts, etc.) can be a problem, though. Also windows can admit IR light from the sun. In the Leap Motion Control Panel, under the Troubleshooting tab, open the Software Log. If the log says something like "Compensating for bright lighting" -- then your device is trying to compensate for IR lighting. Usually this works okay, but if your framerate is already low, entering "robust mode," as it is called, can actually make things worse. You can also turn on images in the Visualizer (press F) and look for any bright spots that could interfere with tracking.
Changing the interaction height shouldn't have much if any effect. It is probably best to leave it on auto.
The Pointable developer hasn't communicated their intentions to us, but it certainly doesn't appear that they are actively supporting their program anymore.