don`t need plumbers putty or drill with clutch... Any drill actually does the trick... Just no rush and that`s it :)
bring aquarium or part of it, in to the shower or bathroom ... and just continues flow of water over glass,drilling area... Start drilling in angle, slow and without pressure, then, when after (few rows), and when the drill has dag in to the glass just little bit, start slowly alingning drill with the glass, till all drill are touches glass...
To take it from all this: water (or ice to cool down, or special cooling sprays), slow, no preasure!