Hello, if you are worried about the size of your atlas, there are a series of optimizations that you can put in place in the editor, such as using polygonal packing to have smaller atlases, and at runtime, such as loading the atlas in the right size for mobile, loading the atlases only for the needed skins, and so on.
When considering how to optimize your skeletons for mobile in general, this page may help you regarding what aspects you may want to improve: Metrics - Spine User Guide
Generally, having that number of skins shouldn't be a huge problem, but it of course depends on what devices you are targeting, the runtimes you're using, as well as the level of detail of the art that determines how heavy an atlas could be. The topic is broad and I can help when it comes to editor optimization, I'll leave runtime questions to my colleagues 😃
