Hey Esoteric,
I have a spine where there is two different body types and multiple heads. When I was using the pinning feature in the editor the skins seemed to layer correctly, however, in the cocos2dx runtime I was not having such luck. In the runtime I start off by setting the base skin first and then the body type and head type but the head was not showing up. I noticed that in the editor the skin placeholders for the head type in the base skin didn't have an attachment and when I attached a "null" attachment (a 1x1 white pixel) the head would show up properly in the runtime. Pretty sure that this isn't supposed to happen, so I thought I would let you guys know.