MeesterB, glad you found them useful! Yeah, your approach seems very logical, and absolutely possible to achieve too!
Things you have to keep in mind:
The basic elements of your different skins must have the same proportions. This is simply because you will move them with the same skeleton so they need to have their core elements
The unique elements of your skin can vary greatly from the core proportions, just be smart about the controls you use to animate them, if they vary a lot but you can reuse a bone for different elements, then you're doing great! if you can't, try to color-code these specific bones so that you won't get confused.
One thing is changing a hat with a completely different one, another is having a hat that is basically the other hat but with different colors of textures. Soren's video shows you how to replace textures for this second case only.
Just in case you didn't already, you might want to have a look at linked meshes Meshes - Spine User Guide: Linked meshes and skins Skins - Spine User Guide
I think you'll find useful these two videos, in the first, two very different skins share the same rig from the start.
VIDEO
In the second, new skins are added. You can see the common elements are the eye color, the face, etc. while most elements differ and get integrated.
VIDEO
(hint: these videos are long, but in their description you can find a menu to navigate to what you prefer)