Plumbing a drilled tank with and eheim 2262 or 2080

[ddaquaria]

I'm curious how to get started with this. I have two tanks that have overflows as well as the bottom is drilled. One of the tanks has euro-bracing so I would like to figure out out to plumb an eheim to the bottom so I can have my dual filtration. I would rather go with the eheim 2080 simply because it is my filter of course on many of my other aquariums.

Please provide any links or advice since my biggest fear is obviously screwing up and dumping 180 to 200 gallons of water on the floor.