What grit do you use? 320 seems like it would cut through the tape.
220. 320 and 400 to finish up. The fins are then papered, beveled edge sealed with CA, and sanded with 400. Note that the 220 I used is the red "3M pro grade precision" stuff, which seems to have a different texture compared to the wet/dry black sandpaper, like the binder goes over the grit as well rather than just underneath. Not quite sure how to describe it. It does clean easier though, and the sheet is thicker. Also, I dry sanded.
Photos are of my Mercury Redstone that I need to work on sometime. They took ~ 30 mins each to sand, so a total of 2 hours or so. Papering goes quick in relation. The knife edge is achieved through the papering and CA, the paper is folded (and strengthened with CA) to extend the rather blunt wood edge out a little and the sanding rounds it (kind of like an ogive) into a sharp edge . I crease the paper beforehand at the edge (not so hard to distort the paper, but enough to help make the edge more distinct. The transition from the bevel to the flat surface of the fin is much less prominent, unfortunately.
Tell me if anything is unclear or you want to double check. Also remember that I'm by no means an expert. (If my build quality hasn't made that clear.)
