I started today by setting up the aft fuselage section on sawhorses and the center fuselage section on a trash can to align them for what I hope is the final joining. I then dimpled the bottom edge of the aft bottom fuselage skin where it mates to the center fuselage bottom skin and joined the two sections. I also installed the F-706 bulkhead, but it will have to be removed once more after the forward edges of the F-773 aft side skins are primed so they can be dimpled.
I put the main longerons in place, but noticed that the top flanges of both very slightly extend past the F-712 bulkhead and could interfere with the installation of the vertical stabilizer. I marked the ends, then removed the longerons, trimmed them with a die grinder, smoothed the edges with a file and scotchbrite, then re-primed.
I then temporarily fit the F-774 and F-775 top skins on each side to mask the F-773 fuselage side skins for priming. I then scuffed, cleaned, and primed the masked areas.