Drilling two holes contained by 5mm chalice? I want to drill two holes next to each other through a...

I want to drill two holes next to each other through a 5 mm cup. It's a fish tank and I want to create an overflow/sump by drilling the bottom pane glass beside a 1 3/4" & 1 1/4" holes. What I want to know is what the safe distance(considering engineering) can the hole be drilled from the edge of the 24"x14" chalice and how far the spacing needs to be from each hole. I don't want the cup to crack.

THanks
How much can I expect to wages for...
Answers:    drilling through glass requires a special drill bit. take your cistern to a glass cutting company and they will do it for you. i wouldn't give attention to it would cost a fortune either.
Par 20 vs GU10?
I agree with him -definitely help yourself to it to someone...glass can be very tricky to drill through!
What's a angelic process of removing rust building...
I would thieve it too a specialist as I don't think it can be done,