I'll be building a stand for the tank, making it a bit shorter front to back so that i can then put it against the wall and finish it off for the in wall build. My question is when working with an uneven floor, in this case front to back it peaks in the middle of where the stand will sit so it will be like a seesaw, what would be the best way to go about it? I was planning on cutting some of the 2x4's into shims of different sizes, but is there anything else you would recommend? Lengthwise it is pretty close, i may have to shim the left side a bit, but my bigger concern would be the front to back, i'd say i would be looking at 1/4-1/2" shim.