I've got a 40L that I'm getting ready to add to my collection. We are going to drill the back so we can use a sump. The question that I have is placement of the holes. My thought is drill both holes near the top (at opposite ends) and use a strainer on the over flow with a down tube for the fill. My wife thinks that it would be better to drill the overflow near the bottom using a stand tube and an overflow box. I realize that her way is the most common but why? Wouldn't my way be just as effective, easier to construct, and also allow for slightly more useable space?