Screen Size Considerations:
When considering what value to set for glyph separation consider these factors:
1. The size of your screen. If you are using a large area on the screen, the glyph separation value can be smaller because the glyphs have a smaller relative angular diameter on a larger screen.
2. The size of the glyph font. The larger the font, the larger the angular diameter. This would vote for a larger glyph separation value.
3. The distance the glyph is from the center of the screen. This means that glyph separation values should be higher for the inside wheel in a bi-wheel arrangement. This is why there are 2 fields for glyph separation on the bi-wheel tab.
A few trial and error sessions should get it to your satisfaction. The same process is also done in setting the glyph separation for Gif files in Html Reports.