Today I made shims and adjusted the saw horses height using a string to get all three of them level. The F-705 bulkhead was sagging a little so I used a bar stool and blocks to hold it up. The forward skins were then able to be clecoed in place. It still took a little jostling around, but raising the sagging F-705 was key to making everything line up. Finally.
My next task was to locate the F-720 armrests. This took a little time rummaging through the parts, but once found, I deburred them so they are ready to cleco in place next time.