Tonight I moved the center fuselage to the sawhorses and finished clecoing the F-776 center bottom skin on. It's a good thing I read ahead in the instructions... For some reason that I may or may not discover later, the instructions have you complete the riveting of the interior seat ribs and baggage ribs to the bottom skin BEFORE match drilling the F-715 outboard seat ribs, and the F-623 aft corner ribs.