So what are you putting on the backside of those patch panels?
I work at a Volvo dealer and I have some really good, oily undercoating spray right from Volvo. The can even has a hose to stick up into the body for hard to reach stuff. It goes on really wet and drippy and ends up tacky and is eventually dry to the touch but it takes a while.
Now that I have a DD this truck is relinquished to garage status, nice weather, and wheeling. Unless one of the other cars is down of course. So that should slow down any further heavy rusting. I hope.

