It is a new choice of cover materials on this forum, thanks for sharing. I was looking into similar mastic material after I came across canvas canoe builds.
Can the mastic be slightly thinned with water for a "skim" finish coat similar to drywall compound technique?
I think using double fiberglass screen is a good decision for better strength on outside.
I see that you have some embedded ribs in the roof, could you share some details of how you did that?
Sorry for so many questions

Great project!
