My in laws live in the Virgin Islands. They have metal roofs everywhere. Their solar panels, attached to the metal roof structure, survived Irma and Maria unscathed. The roof is approximately from the time of Hurricane Marilyn.
There are alternatives to using screws and washers if it is a new construction job versus a retrofit:
"On new roofs, structural GALVALUME steel panels are typically installed directly on purlins. Concealed clips are attached to the purlins, and the panels and clips are joined together by forming, crimping or snapping at the seams.
For most retrofit applications, panels are installed on a sub-framing system which, in turn, is attached to the existing roof structure.”
Here is the link to a pretty useful article I found:
Providing professionals — architects, contractors and building owners — with the most current information available on the use and performance of GALVALUME sheet steel. Featuring GALVALUME Sheet Steel.