drain/return line placement

[Jrodinnola]

Trying to figure out the best plumbing layout in a mr aqua 12g long so I don't have to use powerheads. I'll be using locline screwed directly into a bulkhead(s) for the returns, and a bulkhead(s) with a screen for the drain lines.. sketched some layouts for flow / return placement.. any ideas on improving this? I like the one on the bottom since I can make it a herbie style overflow by adding a rear overflow box, but I'm not sure if the placement of the screen in only the middle will be as effective as I'd like it to be.. feedback please!
http://i122.photobucket.com/albums/o246/jrodinnola/photo2-5.jpg

[Ron1966]

What size return do u plan to use also the drain GPH? This in terms will affect you trying to create the flow your looking for. I believe the simple power head is the way to go. Better control on water movement for corals etc.