Thanks. Yep pretty much what I ended up doing. I used composite shims and did a full base under each of the 8 vertical uprights, then spaced the rest out about every 6". Worked out pretty well, I expected to hear some noises from the stand maybe during the initial fill up but never made a sound so I think it's all nice and fully supported. It's always fun shimming a long tank on the basement floor of a 1950's built house. I think the contractor back then must have been drunk