IIRC, Bagginsbill had a post back in RDNA's Node Cult where he demonstrated how to create realistic skin renders using James and his default hand-painted textures. Unfortunately, that post disappeared into the internet void like much other helpful information.

@Rhia: I use inches as my unit of measure. Also, I just discovered recently that not all textures will render well depending on your selection of Cycles nodes. In one instance, I used the PrincipledBSDF for a new set of texture shaders and got horrendous results. I switched it for the PhysicalSurface Root and the problem disappeared. I need to look into this further, maybe it's a one-time thing but I need to see if it's repeatable.