The pool will fit fine, and it's
reasonably level. I plan on using a children's play pad underneath the
pool to soften the floor.

I put up an 18x48 this summer. I used 1/2' foil backed Styrofoam. I cut
the pieces to fit and duct tapped together then installed the sand wedge.
So far it has given a nice bottom with some give but does not leave foot
prints.

Robert