I’m doing more less same thing but with no overlapping faces and masked textures - that’s because masked is very expensive for mobile. Let me explain:
I’m using something called Mesh Trim. It’s not adding another layer of faces on top of other faces with alpha channel. The parts that should have this “decal” effect are actually a part of the mesh.
Then I’m using 2 UV channels to map both, I don’t bother with the 1st one much:
But the second - here comes the trimming magic:
This way I can create nice trims for mobile devices as well - one mask based material is much cheaper then alpha material, and you don’t get Z-pass artifacts on low end devices.
But that’s just a different kind of story, as it serves a bit other purposes.