Is the roof going to have corrugated metal? What is the top of the roof material? You coukd use the wood as an insulation and install a few sheets of corrugated making the overhang.
I tried to draw a roof structure on my phone. What is lacking is your triangular structures, if you have more wood available, you can try to level the columns, but if you dont want to raise the columns to be level, you can try to build the base triangles using the columns as is.
Your roof piece is a good insulation but i suggest using corrugated with a rainwater channels after you get it installed.
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