C-21 and any of the Tex coverings is like the old apple and oranges thing, C-21 isn't even in the same league. I did A hell cat in the solartex using there blue and white then the fellow I built it for painted the light blue or gray over the Tex, wow, what A nice looking plane. The Tex is so nice to work with, way better then any of the plasitcs.
Balsa USA is where I get mine.