How would you recommend cutting glass with a GreenBull?

It depends on the type of cut you're trying to make and the type of glass. In general, straight cuts can be made by scoring the glass using a type of engraving bit, such as these: http://www.widgetworksunlimited.com/CNC_Specialty_Bits_s/33.htm. Complex curves and thicker glass is usually tackled with a diamond burr endmill and a specialized jig. Here is a nicely done you tube video giving an idea of how that works. https://www.youtube.com/watch?v=HyI111Tn0Cs