Next point - tank levelling

[Aquattro]

So I've built the stand, it's big and heavy, and it sits right across a hump in the floor (almost an inch play side to side). At 2500 pounds, am I ok to use wooden shims on the corners (can't reach back edge once in place) or should I look at great levelling?
I thought of framing in the area and pouring some quick set on plastic to create a mini slab, but that might crack at the edges and be bad....

thoughts?