Moisture shouldn't cause RI but a snake that lays on a wet surface can get scale rot. Of course, you can have 90% humidity without there being surface moisture..
BPs require a much higher initial investment than corns. You would have to price everything and be sure you had the enclosure set up and ready to go before getting one.
Enclosure: tank or plastic tub.
Heat: under tank heater large enough to cover half to 2/3 one side of the bottom.
Thermostat to control the under tank heater.
Thermometer/hygrometer to measure temperature and humidity.
2 hide boxes that are small and tight fitting.
Once you have all that, then you're ready for a BP.
Read the care sheet on this site for all the details.
A 32 qt sterelite tub with licking lid is small and perfect for housing a male BP it's entire life. Unless it turns out to be one of the few males that gets as big as females. Room is less of an issue with BPs as you may think. They spend most of their lives in a rodent burrow or termite mound in the wild. They are seclusive and do much better and eat better in a smaller environment.