I’ve given up on using deburring tools on the skins. If I use it enough to remove the bur, I have the beginnings of a countersink, and that’s bad. There are too many stories of over-deburred holes on the internets. I’m not going to be one of them.
I can deburr with nothing other than a maroon scotchbrite pad without enlarging the holes at all. The only downside is no polished aluminum on the exterior.
Berck, Jonah: 1.5 hours.