Today, I finished working on the 358 and 359 bulkheads. This is one area where the plans are woefully inadequate, as there are two additional modification drawings floating around. One has additional packers on top under the stab mounts. I had ordered the modification parts from Murphy Aircraft and that part went smooth. There is a tab on the lower horizontal bulkhead I had difficulty figuring out, but concluded I needed to make a small angle to tie into the fin spar. In order to drill the angles to the lower horizontal bulkhead, I removed the upper bulkhead and used a long #30 drill bit. I also put/cleco'd everything in place, and use clamps to hold the lower bulkhead in place before attaching it to the side bulkheads. I believe there is a discrepancy in the drawings for the modification, as they show the lower bulkhead with the flanges pointed down. I found that it would not fit that way, and installed it with the flanges up, a reverse of the upper bulkhead.