My bet for Vallejo is also on the left side miniature. It will be interesting to see the results.
I don\'t think anyone needs to spend time painting a miniature up for the lightfastness test. You could instead use a strip of plasticard or extra bases, paint closely comparable swatches of colour on each (blue, red, yellow, and black at the least), and leave them out. A control should be done for each paint brand and placed in a box, which would be helpful to measure how much if any fading has occurred.
Strangely enough, out of all the windows in this place, there are none that actually get direct sunlight for the majority of the day. If I can find an appropriate high sunlight area, I will give this a try.
Kep