Drilled the 1/4" holes through the F745 ribs and ran the reamer to allow for the slip fit of the AN3B pins. I had to remove the foward structure because the 745 rib and 644R were already riveted to the F768 subpanel. Pain in the ass, don't rivet those early, thankfully I had only done one side before figuring it out.
Modified the AN3B-16 bolts and checked fit. Finished the C620, C621, C622 and assembled them with the WD619 and WD618. Unfortunately the F697 channel and the F643-1 channel will need to be removed to install nutplates and make relief cuts. Why in the world wouldn't I have done this already?