Used my buddy Greg's C-frame to dimple the new aft baggage shelf - worked great, in fact I think I like how it dimples better then my DRDT-2.
Then I backriveted the stiffners to the shelf. Unfortunately one of the stiffners interferred with the middle longerons so I had to use the dremel to shorten it in place (rather than removing it) but it was simple and it's ready to go.