Anyone ever use these before? I'm putting up a 16' x 24' shed/out-building on my property in the next few weeks. I plan on using EZ-Tubes for my footings. 3 rows of 5. Going to go down almost 5', compacting a 6" crushed stone base, setting the base section and then using 4 standard pieces. Seems like a very cool product. Looking forward to NOT having to mix a pallet of concrete.