Did some RnD with clear coat and sheen today
This is the outcome. I’m quite pleased with both the looks and the compression.
Using draco compression I was able to get the -glb down to 1.5mb from 24mb!!
Found mesh online as fbx.
Removed all materials and only used principled BSDF with base color, metalness, roughness.
except for windows, where I used alpha blend and a dark gray.
Then I imported the scene as usual using the scenemanager, but then added some clear coat settings to the paintwork. and tweaked the window material some to, because I was unable to set some of the settings from the blender exporter.