After wresling with pepakura for over a day, I decided to give it one more try, unwraping from Rhino. I found out that not all surfaces have the U and V dimensions in the same direction, sometimes they're swapped or inverted. Once I alligned the UV maping, I could reduce the degree of one of those dimensions to 1, and then unwrap the resulting surfacas. Here's before and after shots of the Rhino model, and the unwraped "skin" parts (or as I like to call them "the hard part"). Next up, formers and spars.