I have lots of 6061-T6 aluminum left over from my Sonex build, so I used some of that to make the "rib."
After cutting and finishing the new rib, I used my small bending brake (again, from my Sonex build), to bend the rib flanges.
I drilled holes in the elevator, but will wait to set the rib and drill its holes. I want to fabricate the trim tab, first. That way I can move the rib in or out to get a nice, consistent gap between the elevator and the trim tab.
Once everything is set, I will dimple the elevator skin and the rib, and use flush rivets.