I started the day my checking the fit of the left outboard seat rib and match drilling it to the bottom skin.
After that, I spent a LOT of time in the manual and plans sheets to familiarize myself with how most of the rest of the center fuselage fits together. A little research on VAF and a hint from Con Kelley steered me to Brad Oliver and Mike Bullock's build logs with good photos of how the F-623 corner ribs fit. The joggle in the forward end of the rib is an artifact of these ribs' use in the RV-6. On the RV-7 both ends of the rib get trimmed to eliminate interference with the F-705 and 706 bulkheads. They are later attached to those bulkheads via straps.
To give me an idea of how much to trim the aft end I moved the F-706 bulkhead from the aft fuselage to the center fuselage. While I was at it, I clecoed in the seat and floor pans and the baggage floors to stiffen the assembly and get all the parts in the correct relative position.
To set the proper fore/aft position of the F-623 corner rib I temporarily clecoed on the side skins and determined that the aft edge of the forward outboard flange of the-rib needs to line up with the apex of the angle in the bottom skin so the flange will have good edge distance when match drilled to the side skin (Photo 1). Centering the slot on the apex would result in insufficient edge distance on the aft hole in the forward flange. Moving the rib back this small amount also improves the fit of the aft outboard flange relative to the edge of the bottom skin.
I used duct tape to check that the side skin is in the proper position relative to the bottom skin. (Photo 2). The instructions and plans don't mention it that I can find, but it appears to me that since the side skin sits on top of the bottom skin between the spars, that it should continue that way all the way back to the start of the cone section.
(Continued next entry.)
Determining the fore/aft position of the corner rib.
Checking the fit between the side skin and bottom skin .