Yep, with the little towers of shims spaced at 12 inches, it is a pretty rigid arrangement. When you go out to work on the project, you get a really good feeling about it, knowing that the floor is level front to back and side to side. I used an aluminum 48" level to span across the little towers, which you can get as close as 0.003" to each other in height by gluing squares of copy paper onto the top of each tower, after you get real close with the thin cardboard. It goes without saying that you begin at the highest point in the garage and build to the lowest point.
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