The rear spar of the right wing needed all of the holes in both its upper and lower flanges countersunk or dimpled, depending on whether they were next to the flange of a doubler plate. I also had to ream to final size all of the rivet holes that match up with the attachment fork, and match-drill 6 holes that fork that didn't go through pre-existing rib holes. Finally, two rows of rivets on the attach bracket needed to also be countersunk.
What's next? Some final deburring and scuffing needs to be done on these rear spar parts, then I can prime them.