I owned a sailboat and a Sailrite sewing machine for years... and used to do all of our Sunbrella, interior and exterior upholstery work.
You might want to research Phifertex: it comes in 70% sun shade and 90% sun shade. It is designed for these types of applications that you're talking about... so it might be a good fit. I used the 90% shade and could still see out from it, and it shielded people from seeing in. And it offered great sun protection for being a mesh.
Hope this helps! Good luck!