PovRay by default works in a left handed coordinate system. It also describes the aspect ratio for the entire scene, independent of the number of pixels you use. if you want your circles to be perfectly round, then set this ratio to be the ratio of the dimensions of your image. You may have noticed that I create two light sources at the same location in the PovRay scene. If you used only the first light source, areas in shadow would come out completely dark, which is a bit unrealistic. So I always put a second light source which casts no shadows to light up these darkened areas a bit.
Models made by povscript have a default font and fontdepth used for any labels.
There are a bunch that come with the macintosh and windows 95 operating system. Unfortunately, this is a trademarked font so we can't distribute it. Go find a mac or PC and put symbol.ttf in the include directory of your povray source tree if you need Greek labels. Mac .ttf files come with macinstosh resource forks which causes PovRay to break. It's available from the Info-Mac Archive.