Have you ever used red and green sand? I have black clay, and the sand really breaks it up.
Our problem is the Nitrogen in the soil is "locked up", either phosphorus or potassium is too low to make it available to the plants. It's also acidified from the oak tree leaves. We get massive amounts every year.I went to the local (years ago) garden center and the owner said, well, you can try amending it with lime, but good luck.
I'm hoping the compost will really get the soil "going". I figure I screened about 2.5 yards, so we'll see what happens after it rests this winter. If not, I'll get a couple of yards of top soil.