I am not working in exact order per the plans, but need to do some priming and top coat of the seats before I can rivet them into place. So to keep progress moving along I worked on the seat back supports. These guys go behind and adjust the angle of the seat backs depending on which hinge you have the seat back secured to. It sounds confusing, but is really quite ingenious.. I used the fly cutter to cut the lightening holes, and standard drilling techniques to affix the hinge have to the seat back support.. Came out well..