I wanted a way to secure the side panels without using nutserts that could rotate later and would hold the panels proud of the bulkheads. This needs to be done before the canopy rails are riveted on, so I drilled a backing plate, mounted # 4 nutplates on that and used countersunk 3/32" rivets to hold the plate in place inside the # 4 bulkhead. I drlled all the holes in the bulkhead to 5/32" so I could use the deburring tool from the front (through the holes) ... I particularly don't want any cracks propagating along this bulkhead !
Next, I'll do the same on the other side, but with closer spacing due to the smaller panel height around the throttle body.
