Best foundation to put a 12/16 on?

[randomq]

Easiest way, IMHO, is to put it on 9 concrete house blocks with straps. Beam can rest on your highest corner or a short 4x4+ post of 1-3ft height. Then level the beams with scrap wood shims, and cut posts for the rest of the blocks. Add Simpson ties and diagonal bracing at 45°. Then build your floor box on top of that, with or without a little cantilevering.