When I release the next version of one of my mods, I'm disabling certain complex skins on it because they don't show up correctly. I was thinking about making new skin UVs for this mod, but I felt it would be somewhat complicated and I'm wondering if there's a process involved in creating them specifically for non-official or modded official vehicles. (or am I overthinking this and it's much simpler than it seems? I haven't had access to my computer for a few days and can't verify that it's actually possible.)
It's the same process as when UV-ing something. Object can have different UV-Maps. Vehicles with skin support have a second UV-Map, which is used for the skin (overlay map) only. You just have to switch to the second UV-Map and edit it as you would normally do with any other UVMap