I'm up to to my 3rd set now, with one more to go. 1st set was just getting the process down, next set was testing different scanning practices, calibrating the image colour, and adding AO maps
3 set refined the capturing process and changes to my lighting table along with trying out substance designer to back normal and AO maps.
4th and I think final set of rocks I'll be testing the use of detail maps and see if I can get the texture map sizes down.
After I finish each set I uploaded them to the Unreal Marketplace. I don't expect much, but I figures any sales would help fund equipment or software upgrades. So if you need some unique high quality photo real rock assets for your UE4 game or architectural design project go take a look.