I have done this a few times myself and I found a bit similar to the 7123 bit he listed to be perfect for adjusting the hole size a bit bigger. I also use a chunk of plumbers putty that I form into a ring around the area I am drilling and fill it with some water, the extra water tends to keep the bit cooler until you drill through the glass and then you need either a bottle like he showed or a hose set to just trickle a small stream of water (this is more effective on thicker glass than the spray bottle).
