I've got at least 6 hygrometers from my tupperdors in there that I've calibrated and moved around for double checking. They seldom match perfectly, but all pretty close outside one that is off on temp too.
Two of these are the SensorPush models that track data via Bluetooth.
I really don't want to run a bunch of wire around in there for fans - both the aesthetics and if you attach to the shelves, they become fixed unless you want to rewire. But in my head, its probably the answer. Maybe I can temp something up for a trial.
Anyone have specific fans they run in their cabinets or wineadors?