Just curious; you say 50 X 70 X 8. After you excavate will you have stone delivered? By my estimation you need about 40 ton. Where I am, that's close to two tri-axles worth. If that's how you're doing it will they at least "gate spread" it for you when they deliver? I know that it will have to be dry, I don't think they wold want to back into wet new excavation.