Yo! My flooring might be perfect for your application,...first, I stabilized the rust, used polyesther body fill to repair the small holes and strengthen the floor, satin black enamel, then 1/4" wool/foil backed insulation, and a single rubber mat for the entire floor.
(please ignore the WD-40 overspray on the mat!)
I've added rubber mats to each side that have small "cups" formed in them to hold water and dirt. Works perfect.
Todd.