It says in the warning “enable error coloring to visualize” when you have overlapping uv’s - I don’t know where that is though. 
I’m kinda new myself.
If you’re going to use 3DS Max you’ll have no problem getting answers to your uv questions here. I’m using Blender and have finally found a good method, so hit me up if you use
Blender.
Just so you know, mirrors and glass are a big problem because of inaccurate reflections, mirror in particular is terrible.
One more thing, the post processing volume is your friend. After your lighting is built you can adjust a lot of things without having to re-build.