I finished deburring and dimpling the bottom wing skins, along with the corresponding rivet lines on the ribs. Here's a random shot of the ribs, all dimpled.
This whole series of steps took forever and was boring. I can't imagine doing a whole wing's worth of this – hooray for Quickbuild.
This time around I deburred the skin edges by going over them first with a vixen file to knock off the shear marks, then with an edge burnishing tool, then with a blue (fine) roloc pad on the die grinder. It worked pretty well and didn't take forever like sandpaper does.