Yeah my workflow on my last 3d game required 'layers' in the texture so I had to set up that layering in the shader, rough spray the general idea of what I wanted onto the model, export everything, edit the textures in Gimp to make it look good instead of fingerpainty and flatten them.
Also, the way UV editing selection works is rough. If you don't have a face selected in the model, it simply does not show up in the UV. The UV has its own selection. So in order to single out a part of the UV based on a set of faces you need to first select the faces, remember where in the UV map they live, then select the whole model again, then select the UV points again.
Also, the way UV editing selection works is rough. If you don't have a face selected in the model, it simply does not show up in the UV. The UV has its own selection. So in order to single out a part of the UV based on a set of faces you need to first select the faces, remember where in the UV map they live, then select the whole model again, then select the UV points again.