Looks like you've coated already...great job! Don't know if your gumbo is the same along the river like it is in the North Delta, but just find a big enough water hole and drive through it. Once it dries....it ain't comin' off. Kind of like love bug guts too, ha.
I lived in Oxford for 7 yrs. The humidity killed me, was good to get back here to CO. I'll take a wet day in CO over a dry day in Oxford, ha. I've never seen moss grow on asphalt until I moved there.
Our house was rarely open. Either the heat pump or A/C was on. During the summer, I ran two de-humidifiers at night, one on each floor, to pull the moisture out of the house in order to get the relative humidity down to a comfortable (for me) level. Otherwise I would be running the indoor temp around 65F. So the de-humidifiers would pull the water out, the A/C would pull the heat out and what moisture was left, ha.
So...with all that said. When I did any sheet metal work on my '77, I moved one of the de-humifiers into the garage.