Boy, you just poured gas on the fire. You can set your tank up a hundred different ways. If you want a skimmer then you are probably better of having a sump so it is out the way. Due to your tank dimensions you also have the problem of low surface area compared to water volume. The sump will help overcome this.
I am 99.9% positive that the tank is not toughened glass. You could use a wear which would clip on the tank, then you would not need to drill. If you are going to drill, I would drill the back panel and not the bottom. If it cracks when they drill (not likely to happen) it will be easier to repair. It will also mean that you don't have to mess around with your stand. I assume it is an Aqua One stand.