I installed 2 on the sloping part of my small RV in Europe. Very easy installation with Sikaflex glue, they weigh nothing ... Among other advantages: the wind does not take in.
I use this RV especially in winter, so the temperature is cooler than in summer. And especially, as the sun is rather low in this season, the inclination promotes maximum insolation ... provided to park the vehicle in front of the sun!
I went from 100 W to 340 W at a light cost; I took the opportunity to improve my system by changing the PWM controller for a MPPT of 40 A.
All in all a very effective system to feed my 2 x100 A flood batteries (which I intend to replace soon by a single LiFePO4 100 A) as I did here in Canada on my PM.