Something for you to think about...not trying to make you spend more money or that...
My main tank overflow box is on the one side right in The middle as it gave me about 8inches on both sides of it and it bothers me at the beginning (less room for swimming and really hated viewing the overflow box)from a guy that likes to cover all the back and sides with rock work...
It bothered me so much over the years that at last decided instead of fixing the tank by moving the overflow box....just build another tank to my specification
Trying to tell if anything is bothering you now about your tank. .then fix it otherwise it will haunt you later on...