Gave myself a pat on the back as it ended up fitting very nicely. Lots of trial and grinding and fitting back and forth. The Klasfab panel is a great fit. It goes all the way to the top of the cross strengthener, but I trimmed it down as I wanted the original metal to stay securely in position.
First lot of work I've done in several weeks due to having a bad back. Boy was it hot out there today. I'm trimming back the metal for the new rocker panel.