How to mount solar panels thin plywood bighorn roof

I did exactly what you're doing about 3 months ago. After a lengthy bit of research and practice I use 1/2 well nuts. Drill a 1/2 hole, lap sealant around the top, insert the well nut, a dab of lap sealant on top, place solar panel, screw in place (the rubber well nut expands and seals and grabs the roof, more lap sealant ontop of the screw.

Did a number of hard yank tests and there's no way these are moving. My Montana has an aluminum frame.