I saw an episode once where they added stringers 16" on center on top of the stressed skin roof (I believe 1x2s) then added plywood on top of that to put the shingles on. This left an air gap between the top of the stressed skin and under the shingles. They then ran continuous venting along the ridge and soffit. To me this seemed like overkill, but?? There are several stressed skin panel manufacturers, I wonder what they recommend? Hoping for more unput, Dodgeman