Took apart the vertical stabilizer assembly and deburred all holes for updrilling. Then clamped down the vertical stabilizer assembly again, made sure it was square, then updrilled to 1/8" for riveting. Pretty easy, but needed the 12" 1/8 bit quite frequently for clearance.
After updrilling and clecoing, I disassembled again and deburred everything. Over the days of working on this many of the parts ended up with scratches and nicks, so I spent a long time sanding those out. I also hit everything with "Goof-Off" to get rid of labels and accumulated sharpie marks and skin oils. As I always to I'll wifew everything down with denatured alcohol before final assembly.
I also test fit the VS skin; it looks like it will take some moving around to get just right, but I managed to get an alignment I'd be very happy with, so I think it will work out fine if I just take my time about it.
A problem location. Luckily the Bracket Below is Removable