Fuselage: Forward fuselage lower structure.

The plans require a break of the bottom skins at an unusual location.

Update 26-Aug-16:   No they don't.  The edges of the skins aft of those lines get a break.  See here on VAF.  Whoops.  When this was ultimately riveted to the mid fuselage lower structure, the edges had a good layup regardless.  These are the kinds of mistakes that make one feel like a fool.

Here's how I approached that, with a little elbow grease.  Don't do this.  See above.

One pair of my VENT-00001A-L/R vent sides did not come with the holes drilled.

Not a problem.  I just drilled them in matching to the other sides.  If you look closely, you'll see I was a millimeter or two off, but everything still lined up well on a test fit with the firewall and vent.

The vent inlet assembly uses some stainless steel rivets, MS20427F3-3.5.  I chose to squeeze these.  It takes noticeably more elbow grease to set these rivets as compared to an aluminum AN426-AD3-3.5.  Below are the assemblies.  I only need to dimple the holes marked "F" on the right (which is the left assembly) to accommodate the error I made in dimpling the left firewall side.  I'll need to pick up a set of dimple dies so I can grind down the male die to fit that confined area I need to dimple.