I ended up putting down about 3" of peat moss (8 - 3 cubic feet bags) over the grass covering a 16' x 16' area, I then topped off the peat moss with 8 sheets of R-Tech 3/4 in. x 4 ft. x 8 ft. insulation taped at the seams. The 3/4" insulation was much more flexible then the R-Tech 1 in. x 4 ft. x 8 ft. insulation which was very stiff. I did not use the Gorilla pad because it was so thin and seemed like a waste of money, I am sending it back. I filled the pool and so far everything seems to be good. Set up time from start to finish, filling with garden hose (2,800 gallons) was about 8 hours. Grandchildren will have a blast today, Sunday!
JPC24