::FACEPALMSLAP:: Relative humidity is a term...take it literally...it means relative to the environment. If you are blasting your heater to keep warm it could dry the ambient humidity outside of the humidor.
Lot's of variables...boveda + quality tupper/(generic named tupper with proper sealing) is more or less a helluva lot better than any wooden humidor ever. Keep sticks isolated in multiple batches in multiple containers and decide what boveda pack is right for you.
If you are only keeping a few boxes or less this is really the best way to keep them good. Humidors are awesome when calibrated properly, but too few times people just throw stuff in and over or under humidify.
Boveda/tuperdore, is so much less a gamble and works great. I can't tell you what the relative humidity is or how to calibrate, but I can tell you it's always better to be dryer than wet.
Cigar shops usually keep wetter because split wrappers mean lost sales...Have fun take her easy and enjoy. Damned you I want a cigar now.