Seat Back Supports and trying to understand the tunnel cover.

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..

Then I started troubleshooting the angles that support the tunnel cover.  These guys are Z type angles like used on the tank supports, but as you can see from the blue hashed lines, they need very complex cuts during the fabrication process.  I haven't figured out how I am going to do this, probably a combo of die grinder and band-saw...