I'm putting in the floor pan -- I misdrilled the supplied part, so I got a piece of .050 and recut it on the sheer at school.
I choose to use rivnuts instead of the self-tapping screws because I wanted to more reliably install/remove the floor plates.
With the rivnuts in place, I used a strap duplicator to drill through.  This proved a lot easier than "drilling from the bottom" as suggested in the plans.

This worked out well since I ended up installing/removing the sheet multiple times to get the cut outs for the brake brackets where I wanted them to be.

Still some final shaping and deburring to do, but the other plates in the baggage area should install a little nicer.