can someone give me advice on setting up a herbie overflow

[xtreme]

Another tip is to set the clutch on your drill to a very low setting so if the bit binds up at all the clutch will kick in and hopefully prevent it from cracking. Drilling holes is easy, just take your time and keep the bit wet. Also don't drill to close to the edge, whatever size you are drilling leave at least that much space between the hole and the edge of the glass.