It is a clever solution. I especially like the last suggestion of hanging gutters on the edges as bumpers/rain collection. Although, after thinking about what I would need to make the roof decapitation-proof, it seems like a regular wood+shingle roof would be the least amount of work. Same with the polycarbonate panels -- sounds simple, but then factor in purlins, closure strips, crack-proof screws, and it becomes a big project.
Now we're talking! By "roofing paint", do you mean something like this?
https://www.homedepot.com/p/Henry-5...tive-Roof-Coating-0-90-gal-HE587146/202091035
It would be brilliant if this is all I need. Didn't even realize such a product existed until I searched for "roofing paint".
The weather here is hot and dry, think California desert. A few times per year we get some heavy rain. This would be perfect.