ok, roughly 100 cubic ft. use an Accumonitor or a Habitat Monitor to control the humidity. With 100 cu ft, I would try 4 humidity cannisters that you would see in a typical cigar cabinet. As long as the closet is sealed fairly well, the 4 cannisters should do the job. If you find that you need something more robust, the humidity controllers can be used along with a Sears room humidifier. Dont rely on a typical home humidifier to accurately control the humidity level. Both Matt from Avallo, or Bob from Aristocrat would be able to help you.