Posted By:
MillerhouseLeon,
The Red Sun backs are tough but something along the lines of a Carolina Brights T206 back. Helmar backs are impossible. I, too, know of no more than three or four, and I've been collecting these for forty years. That would make them impossible, along the lines of a Cobb back T206 -- if one assumes that Cobb backs are T206s (and let's not start that one again).
Neither cigarette brand seems to have issued the unbacked colored silk variety.
Dan