Although not in the assembly manual, I learned from the RANS CLAN forum that the "sharp" tips on the forward ribs (as supplied from the factory) could damage (make punctures or dimples) the stabilator forward skins when they are wrapped around the ribs.
I used a disk sander and 3M polish wheel to round and smooth the noses of each forward rib. This step will prevent any "dings" on the forward skins when they are installed on the ribs.