G morning @sarahlenker !
Thank you so much! And forgive me, curiosity got me and a simple question became a discussion 
for this I ask you, can I continue? because there are other things that I would like to ask you, thanks again for all the sources you have attached, I will gradually recover them all! Instead, regarding the atlas, I have heard/found opinions that I find a bit contrasting and confusing. For example,a guy told me that it doesn’t matter how many textures you put inside an udim, what matters is that they have the same res and shape.
Now I’ve created 1 set of 12 colors/normals/rough baked at 1k, so it would be 3 atlas (one for each channel) of 12 txt. Can I scale them and insert all 12 in a single file/udim?