The new guide discusses how to work on procedural skin using Mari and maps from TexturingXYZ. Basically, you can use the same workflow for creating skin maps. The artist discussed a proper setup that can be used for different creatures.
One of the keys here is using Mari's possibilities. First, you need to learn about a Material node which can let you quickly texture several assets, "without the need of re-creating your complete nodes-tree." The latest Mari allows users to treat Material as Smart-Materials by using Geo-channels.
You can find the full written guide on using TexturingXYZ maps and Mari's features here.