I'll chime in here ifin you don't mind. I live in Houston and rust is pretty much a nonissue unless I am careless. Humidity on a dry day is 50% and 75-80% is the norm. Humidity is not a problem, it is when the humidity condenses on the tools surface that you have a problem I actually have more of a problem with sweat dripping on the tool surface. If your tool is cool and exposed to humid warm air you will have a problem. If you air condition the room and warm humid air is introduced you will have a problem. As long as the equipment remains the same temperature as the humid air around it you should not have a problems with condensation and rust. For those times where you might not have the perfect environment apply 3-4 heavy coats of TopCote initially to the cast iron surfaces and buff off. Follow up with and extra coat every 6 months or so.