Approx 18 months ago I installed 3 window awnings. I was advised to use Rivets, which I did. The key was ensuring proper fastening was that you knew the thickness of the fibreglass so that the correct size Rivet could be used.
Since installation I have never had a problem, even though they have been left out during extreme weather and high winds.
Dave & Ginny
2012 Bounder 35K, & 2009 Mazda Tribute