The complete drivers side pan is now out. I’m glad I went ahead and pulled it since there was quite a bit more rust than I expected under the seat pan. I now need to get some full length pans ordered so I can lay them in, mark off the tunnel and clean up that cut.
The export brace is now in. A little digging and a post on 69Stang.com validated this as a common problem. I ended jacking the shock towers apart with a small hydraulic jack and some pipe and the brace dropped right in.