I think I'm good now, thank you though. I'm just concern if this guy can make a precision job.
No much I can do about it. All the other places I've found here so far only work with high volume products.
I'll probably buy the top layer as well. This one doesn't require the same thickness but I will still make with 1.5mm.
The plan is fill the gap with a 5mm Polycarbonate "ring", so above the backplate should be 6.5mm total plates.
From the schematics that I saw, this is the measure I need to avoid the "floating" design.
The bottom case should also be PC.