Hey Indy1, if you still want to drill glass, make sure the pane you are drilling isn't tempered (look for a sticker or call the manufacturer),
in addition to the bit, when I worked at an lfs, we used a ring, I think it was rubber, around where we were going to drill the hole and we filled it with a liquid before drilling. I know this is vague but it was a few years back now. Maybe someone who works at one now can fill in the blanks. Or I can try to find out for you can get back to you.