The valve that I refered to is from Surplus Center. Look it up in their catalog. That valve had been recomended several times on the forum. I think Junkman had used it, but not for sure. Anyway,. I really like my installation. I don't have tilt on my box blade, but what I have done is install a dozen wheels on the back of the blade to lift the BB and roll out the dirt as it is spread. This is how I was able to build up a pad for my new work shop. Spread and compact at the same time. I would lay down about an inch or two of clay, dampen, and then run my sububan back and forth to really pack it in tight. Portions of the pad are better than two feet thick. It was harder to dig for the footings through the builtup pad than it was in the native soil. What ever valve you use, I would go for at least a two spool valve.