Worked on fit of the EF-602, EF-601 front and back channels. This required installation of the seat floors (F-647? R&L) and securing them with clecoes to ensure that the position of the EF braces was correctly determined.
One problem was the top of the EF-602 channel attachment to the back of the F-605 seat back brace. The F-605 has multiple layers and is too thick for the cleco to securely hold the channel and the cleco launching itself when it slips out. I decided to drill out the channel and seat back brace so that the screw and nut attachment could be made. Unfortunately the nut is a nylon locking type and I didn't want to tighten it too much (these are 'one-time' fasteners and should be replaced if tightened). This wouldn't be a problem if I had purchased some generic fastener hardware, but hindsight is a wonderful tool.
The bottom of the EF-602 and EF-601 both require K1000-08 nutplates be installed in the ribs, so these were located and installed. Of course, this is a multiple step process of installing the seat floors for fitting and removing them to install nutplates, then re-installing for further fitting. This iterative process can lead to looking for shortcuts or failing to fully secure the floors before proceding. Caution and patience is required.