Drilling a tank

[BCOrchidGuy]

I've got two options with my new tank. I can use a glass drill I got a few years ago that worked well for 10-15 gallon tanks but the new tank is 5/8 inch glass. It's not a diamond bit but a steel hole saw type thing but you use a compound/abrasive mixed with water.

Or, second option would be the diamond bits with a dremel tool. I could either drill out the hole for a bulkhead or I could do the overflow type thing in the back of the glass and build an overflow box on the back of the tank.

Any thoughts or opinions would be appreciated.

Doug