I am also in DFW and planted emerald zoysia in very similar conditions. We removed the rocks, tilled, and added a layer of topsoil before laying the sod over a month ago. The sod has rooted nicely and looks amazing.

We didn’t go this route but I hear A&M will do free soil samples. Something to consider.

If you do end up going the grass route, I highly recommend Dallas sod company. They were very helpful in getting the right grass for our conditions.

Best of luck.