Final hole enlargement and alignment adjustments for 'fit & finish' - tightened in a few screws to double-check it.
Most of the evening was spent on the process of using a clear plastic to find the rib and fastener alignment described on the previous entry.
Final result is somewhat less perfect than if the seat floors were being installed on "clean ribs" (no fasteners). However, the end result of the new F-639 & F-640 is more satisfactory to me than the workmanship of the first owner. The hole alignment in the seat floors left a lot to be desired, cosmetically and structurally. The biggest problem was in the removable rib and over-lap of the two skins. That alignment was crooked and strayed by 1/2" at the fwd end.
The taper on the fwd side of the skins, to allow clearance with the gear mounts was not described in the manual or drawings but without doing this the edge of the floor skin would be under the mount and interfere with a flat fit to the wing spar. It was intuitive to trim it back.
