I started the day by dimpling the second side skin, and the aft halves of the F-711 and F-712 bulkheads.
I then fabricated a filler piece so I could use the original shim I fabricated to replace the full-length shim I misplaced (photo 1). I scuffed, cleaned, and primed this part before final riveting.
I then riveted and bolted the F-712, F-711, and WD-409 into the F-779 tailcone skin. This turned out to be much more of a challenge than I expected, and had to drill out and replace quite a few rivets.
I finished up the day by assembling the aft fuselage in preparation for final riveting. For those not yet to this point, DO NOT cleco the side skins to the bulkheads before inserting the J-stringers. There isn't enough clearance for the dimples in the stringers to pass between the skins and bulkheads, especially along the top edge of the F-779 tail cone skin.