if you need to adjust something quickly - turn proxy into mesh (when visible as ‘full mesh’), change mat IDs, tex coordinates or whatever and export proxy again.
Even with one vrayproxy + uvwmap on top, it only renders the preview
yes, that is how it works for the moment. We are working on fixing that behavior.
How do you assign materials on a vrayproxy with the correct uvwmap information (scale position etc) then ?
As piotrus3333 mentioned the proxy keeps UV information in its self. Therefore you need to apply the UVW mod before exporting the proxy.