I've decided to prep everything and prime before setting any rivets so the first few days of this has been a ton of hours drilling, counter-sinking, bending and deburring. Using the 3M wheel saved me a lot of time but there's several places that I had to do by hand. Fluting on the other hand took like 20 minutes, so it's not all bad.
I also drilled out some #30 holes on the spar and spar caps where they should have been #40 and so I decided to replace the spar (which was not cheap!). But with minimum edge distance at a premium on this spars there really was no decision. Lesson learned: Slow down and triple check before you drill!