I ended up locating the pre-drilled hole in the F-729B stiffener so that it would just barely encompass a hole in the F-729C short angle with minimum edge distance (photo 1). This allowed about 1.5D edge distance at the aft end of the stiffener. If I were to make a new stiffener, I would make it about 3/16" longer. I have not yet final drilled the hole attaching the short angle to the stiffener. With very little force I could tweak the assembly and see relative movement between the two parts. I believe I'll wait until skins are clecoed on to stiffen things up a bit.
I then assembled and final drilled the F-707, F-708, F-710, and F-711 bulkheads, including fabrication of all angles and bars. I left the F-711C horizontal stabilizer attach bars about 1/4" long and undrilled above the bulkehead (photo 2) until I can take some measurements and confirm the fit of the stabilizer.
I only clecoed the F-712 bulkheads (far left in photo 3) together. I want to study the installation of the tailwheel spring bracket before doing any work on this part.
The bellcrank rib, channel, and stiffeners in place and drilled.
A rather convoluted clamping arrangement to positon the F-711C angle for drilling.