Empennage: Horizontal stabilizer. Match drilling and deburring.

To make better use of my time priming, I've jumped ahead to prepare more parts for the event.

Both horizontal stabilizer spars have doubler plates in their centers.  Deburring can be time-consuming without the right tools.  For the intersection of the forks, I used a small flap wheel (left).  It makes for a quick, great job in those tight corners (right).

My 3M Scotch-Brite fine-finishing sander perfectly smoothed out the lightening holes in both spars.

The rear spar has "caps" that must be both cut on an angle and then match drilled to the spar.  I'm guessing these caps help stiffen the rear spar to prevent distortion when the elevators are engaging in significant force-creating AOAs.

When match-drilling the second cap, I kept the first cap on the spar thinking it will help stiffen things up better.

After all that's done, both spars get their #40 holes countersunk for the skin dimples.  Of course,  there are 18 holes in the rear spar that are cut for flush rivets instead.