Hi,I have only a small 40w panel. I didn't want to make any holes in my roof. This is only a test. Considering the tiny screws that came with the panel. I scuffed up the metal roof with sand paper and went with 1/4in plastic or teflon bolts mounted with the head standing on the roof embedded in a good amount of 2 part epoxy. The head is completely covered with the epoxy with the glob about the size of a 50 cent piece. For the wire Lowes sells plastic cable clips that have tape on the back side and a channel for the wire to clip into. We drove 3000 miles and saw no problem. Maybe the larger panels would have more tie down points and this could work. Bill