Looking back, I think I spent too much time grinding away at the rust. The beauty of POR-15 is that you can “Paint Over Rust” which is where it gets its name. I could have saved a few hours by just wire brushing off scale and then etching and coating the trunk floor.
Total outlay for materials: about $150, but I have lots left for future rust-proofiing
Total time spent: about 10 hours. 8 hours prep and 1 hour painting two coats on