One thing you don't want are rubber backed mats as the heat can affect the backing.
I agree to the above regarding rubber backed rugs, like bathroom rugs. Any rug though will be heated up. I would recommend you monitor them and see what works best for you. The #2 setting seems plenty warm for us.
Regarding the wet bay there are temperature settings on the dial. Look for 40. The recommended setting. Jeff
2021 Tiffin Allegro Bus 45OPP
2014 Tiffin Allegro Bus 40SP, 450HP
2015 Jeep GC, Air Force 1, Roadmaster Nighthawk