This is really helpful, thank you. I'd totally missed the separate texture export from Spine, to multiple atlases based on folder structure.
What's the workflow with adding eg. weapons? Let's say we have a single weapon referenced in the Spine skeleton/project but there are 20 weapons in the ../Images/Weapons folder. Texture packing from Spine will include all of those weapons ... but how do we then reference them from Unity/code? Or is the expectation that you manually add each to the Spine project file, set pivots, set it up as a skin?
Trying to test this out, I added an extra weapon image to my Weapons folder, re-ran the texture packer from Spine and, in Unity, the UVs are then broken for the weapons atlas (think I'd expect spine-unity to gracefully handle the changed atlas here).
Before: 
After: 
Reimporting the .atlas file in Unity doesn't do anything, reimporting the .json Spine file fixes the UVs for the weapons atlas but seems to create a new (unwanted) material named '<atlasname>-<pagename>-Screen' with the wrong shader (Spine/Blend Modes/Skeleton PMA Screen) assigned to all of the atlas sprites that have no fully opaque pixels (I think!).
Looks like this: 
The blue areas are where there are 'glow' sprites set up in Spine to pulse transparency to make it look like the blue lines on her armor are glowing.
Once it's in this state the only way I could fix it was to delete the exported skeleton from Unity and re-export it from Spine then close/reopen the Unity scene to get the character to show up properly textured. So ... this seems like there are some bugs in how spine-unity handles file changes/reimporting ... guess it's still the same question fundamentally though - what's the expected workflow here? Thanks!
Edit - ok, so I tried just adding the weapon in the Spine file as a new skin ... looks like the runtime will fix things up if done like this. Still unsure how this would work across multiple Spine characters. Let's say there are 10 characters and we want to add 1 weapon for all of them to use this. Using this workflow we'd need to add a new skin to 10 different Spine projects and re-export all of them?
