Don't, I say again, DO NOT try to drill a hole in the glass.

The tempered glass has a sufficient residual surface compression

to insure that it is nearly impossible to start a crack in it.

Consequently it is balanced by an equal or greater tension in

the core of the glass. When you drill with a diamond core drill,

it'll go pretty good until you get through the compressed layer

and when you reach the core, a sudden series of fractures will

relieve the tensile stress there, resulting in the entire indow

being reduced to pieces about 1/4" long and roughly equiaxed.

(I was going to try to do this while I was in Panama and even

bought the diamond core drill. Caution told me that it would

be prudent to try it on a window I didn't need first. Sure glad

I did! Pieces of the glass turned up for over 2 years following

the incident, even though I cleaned exhaustively for several days

straight. During a tour of the Ford auto glass factory in Tulsa

I asked some of the folks there about this and they flatly told

me, "Once it has been tempered, you can NOT drill it, cut it, or

even chip it without a complete destruction of the window.")

I have had pretty good luck with the double sided foam adhesive

pads used to stick stuff to walls, mirrors, etc. It has held my

vent windows to the hinge pins for 3 years now, which is about

2 1/2 years better than with epoxy, Krazy gloo, etc.