Get the tank drilled instead of the overflow box, $20 a hole is well worth it. 
 
I had a 110g and a 50g in an apartment second floor, and it was built in 1950.  I just made sure I ran across the beams, not with them, and put the 110 against the wall where it is stronger.  The 50 was in the middle of the room with no problems. 
		
	
		
		
		
		
			
		
		
		
		
	
		
		
	
	
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