Overflow questions

[Vstar99]

Hello All
I have been stuck on my project, building area for 55 gallon tank. My issue is that i have 2 rooms that will be separated by my tank. The tank will act as my separating wall. With that said my plumbing will be kind of hidden by the sheet rock. it pretty much complete but my concern is that way i built it i have little space for the overflow box (hang on, on the side of the tank not the back due to that both side of tank will be visible). I have illustrated 2 overflow boxes in url. Need info on which one is best. pros and cons would be helpful. In this case then i will modify wall to fit respectfully. thanks in advanced - E!
http://develop.webheadgroup.com/naca/overflow_ill.htm