After re-installing the fuselage splice plates after reworking the lowers, started to reassemble the aft fuselage for alignment.
Positioned the forward-most lower crosstie and clamped into position. Ensured 40" width between the fuselage sides.
Marked up the bench for fuselage centerline to ensure squareness. Got out the lower skin and set it in place w/o drilling just to make sure things would fit well together.
At this point, I have a problem. I cannot square the aft fuselage. Dunno if I drew the lines wrong on the workbench; re-checking about 8 times they all seem OK. If I line up the front edge of the fuselage, the tail end is not square with the front. I can get the lower skin to fit relatively well onto the lower side; it's just right at the rear-most vertical post that holds the tailwheel that isn't square.