Have you considered a box blade with scarifiers down for what you are doing? It would go to about the depth you want and then you'd have a box blade as a bonus.
Using a box blade in a checkerboard pattern will really bust up the ground in preparation for discing. It generally won't pile the sod or rocks either in my experience. Long, hay type, grasses will clog it but they will with a chisel plow, also. Mow first and let it dry out to avoid that for the most part.
You have a LandPride 72" box scraper so you may have the right tool at the ready.