After lots more decifering the instructions I've dome to the place where I need to fabricate the tail tiedown assembly. First I had to remove and reassemble the rear bulkhead. Next I drilled and tapped threads into the tie down. The I trimmed off the tie down flanges, drilled the rivet and bold hoes, deburred, primed and finally assembled with clecos. I won't rivet this together until I dry-fit and rig the elevators.
Tail tie down assembly drawing
Completed rear bulkhead and raw material for tie down