The inboard arm of the steps are secured with delrin blocks. I drilled the holes in these using the drill press and match drilled them to the ribs.
I decided to add a doubler for a bit more support as there was some flex in the rib when transferring weight to the step.
I matched drilled rivet holes, deburred, primed, and installed the support blocks.
I still need to drill the step bolt holes and prime the steps but I’m going to hold off on that for now.