Reassembled the aft fuselage, tailcone, F-706, and added the F-710 bulkhead. Used shims to level the fuselage on the sawhorses. Used strings and plumb bobs to check fuselage for twist. All checks came out right on the money, but did the checks a couple of times, just to be sure.
Began drilling the left upper J-channel by lining up the centerline in the holes and match drilling with the skin. Worked foreward to aft, drilling and clecoing every few holes as I went. Went back and drilled and cleco'd more holes. J-channel flexed more that I expected and had to pay close attention to keep holes on centerline. Finished one J-channel.