I am about done with the tailcone, but am thinking of NOT riveting the top piece on yet. Somewhere I thought I read that it worked out well to leave that off until further in the build. I cannot find anything like that in the archives though.
Different subkit, but it has also been suggested that the bottom skin of the fuselage not be riveted on until the fuel line plumbing is installed--particularly since one of the fittings can't be comfortably installed with the bottom skin on.