Sort of the approach I decided to adopt too, although the reasoning is the drill bits were $20ish, and the labour to have someone do it were $35-50ish depending on who I asked. At those prices for the bits it doesn't matter if I only get a dozen holes out of them before they are too dull.
The trick is keep the bits wet (use plumbers putty or a water reservoir ring), go about 1/4 speed on the drill and very light pressure. You're basically sanding the hole out of the glass not drilling it. And back off the pressure before you're about to punch through, if the glass is going to crack, this is the point where it's likely to happen. >1/4" thick is easy to drill without incident, 1/4" and less it can get a little dicey so it's best to have a scrap piece you can practise on if it's your first time.
Also FWIW there are plenty of instructional vids on the net, think even bulkreefsupply.com has some good ones there.