here's a fellow Thor owner (not sure if he's on the Forum any longer, his last post was a year ago) who installed a HUGE rooftop solar system on his Axis 25.2
several of you current Forum participants are on this Jan-2016 thread
what's interesting here is that he used 3' aluminum angle pieces as mounts to fasten his panels.
if you look closely, the aluminum pieces are inverted under the panels
he did not use screws, but rather Eternabond tape on the underside (or so he says)
here's the thread...
Outfitting solar on Axis/Vegas
here's the photos of his 480 watt / 3 panel install
Huge 480 watt solar install