RE: Building a better Viper wing
I like to use Perma-Grit sanding blocks for shaping leading edges, among other things. They are very straight, very long-wearing, and have 80 grit on the one side and 120 grit on the other. After doing the basic shaping with the plane, and two stages of Perma-Grit, I then switch over to a padded sanding block, just to smooth the surface up with 220 grit or so paper, not really changing the contour much any more. Good enough for film-covering. Of all the tools in my shop, the Perma-Grit sanding tools are the ones I couldn't do without.