Drilling Aquarium

Hello Everyone:

I have a 135 gal tank which is dormant (dry). I was in the hobby a few years
ago and gave it up. Now, I'm thinking about getting back into it and would
like to try something different. To get the flow I need, I'd like to drill a
hole (or two) in the bottom of the tank and build an overflow box
(internal).

Q1. Should I have two holes? (one on each side)

Q2. Should I have the return come back up through the overflow? (I was
thinking of putting the return on the other side of the tank)

I've seen some different configurations and was wondering what is the right
thing to do. I figured some of you probably have some experience with this
and I'm hoping to get the pros and the cons of having an internal overflow
and return.

Thanks in advance.