Back to the leading edges. Today I started fitting the inboard ribs (408s) to the skins. These are the only ribs that are not pre-drilled, so they take a little extra work. Here are the steps I took:
- First I fit the ribs in the skins as closely as I could get and marked every hole with a sharpie. This was so that I knew where I could flute.
- Fluted the ribs.
- Replaced the ribs and clamped in place.
- Drilled the aft flange to the spar.
After that it was time to fit the tank attachment piece (forget the name right now). This takes a little work, but the instructions are straightforward. 
Here is the rib and tank attachment in the process of being match drilled.