I drilled a couple of 1/8" holes and put in some #12 sheet metal screws. I wanted to put the support in temporarily so I can see how my floor patch will fit.
I lined up the support at the 8" mark before I put the sheet metal screws in.
This is the piece of floor I originally cut out. Just checking it out to see how it fits. Where the yellow marks are, I will weld that side first and then I will cut the other edge to fit with the new pans. You can see the little sheet metal fasteners, I'll use those.