I see you do it wrong.
When calibrating with the "board" method. You should keep a board facing (or backing) depth sensors. And move it closer to and further from sensors, and from side to side. So that sensors always see it as a rectangle. Look at the sample video.
https://vimeo.com/68566872When calibrating with the "light" method, a light marker should not be that big. You say that you tried to use smaller light, please provide this video as well - I'd take a look at it.
If you have PS Move controller - you can use it, as it has a good size. See wiki to find out how to make it glow with iPi Recorder.
http://docs.ipisoft.com/Motion_Controllers#Recording