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-Ambient Occlusion: Overlay works most of the time.

-Details: Default blending mode.
-Trims: With this one you will need to use overlay or smth.

-Shading: Overlay
-Shading2: You can just color this layer whatever color you want, don't leave it white please
-Shading3: This can be used instead of the original shading, it's the improved one.

-Lightmap: This is a depth layer. Use it above the paint layer with low opacity 
on a blending mode of your choice, it is not shading.

-Below these layers you can make your paintjob, you can use the paint.png
included as an easy mask or whatever.