How many holes can I safely drill in a 40g AGA breeder?

[MarineGirl411]

Hello everyone. I need to know how many holes I can safely drill in my 40 gallon breeder aquarium? So far I have 2 1 in holes, and 1 3/4in holes. I need to drill 1 more 1 in hole to accommodate a new pump I bought. I just wanted to know if this would be safe to do, or if I would risk cracking the entire tank with water pressure due to the tanks glass thickness. Here's what the holes look like that I have so far.

Could I safely do it if I place it further to the left side of this picture? About where the other 1 in hole is towards the bottom middle of the tank? Please let me know. Thank you all.

 

[herostar]

One more will be fine, just try and keep it at least 2" from your other holes.

 

[MarineGirl411]

This glass is 1/4 in thick. Are you sure 1 more 1 in bulkhead would be fine? Anyone else?