A question from Twitter today: "a client got a trial, which came with vWSE licenses. We need to test vPC is it possible to get a trial for vPC licenses?"
Answer: The GRID software license is a superset so valid for that edition or lower, and those corresponding vGPU profiles. For example, if I have 100x vWS (virtual WorkStation) edition licenses I can use them as vWS or vPC (virtual PC), but not for vWSE (virtual WorkStation Extended). I assign the desired vGPU profile in the guest settings, e.g. M60-1Q, and on boot it will pull a license from the license server, leaving N-1 for remaining licenses.
Note: In the profile (e.g. noted above or M60-1B) Q = Quadro Driver and so has professional visualization features and performance, B = non Quadro driver