I've spent about 3 hours working on the firewall trying to get the scratches out. The scratches end up being on the interior side of the bulkhead and fairly close to where the angles get riveted on, so they are not absolutely horrible.
I used everything under the sun to get the scratches out. Primary, I used maroon and white 3M scotchbrite with toothpaste to remove and "re-polish" the firewall.
Its much better than it was. But some of those scratches weight heavy on my mind. How demoralizing for the build!