Hey Jim, general guidelines even for "dry" storage recommend a minimum (!) of >60% RH at room temperature, as with temperature variations, the absolute amount of water fluctuates wildly. Your tea is probably drying out, which would manifest with flat, muted flavors and rough mouth feel. See http://chadao.blogspot.jp/2008/06/persp ... -puer.html for an excellent 5-part primer on what storage is, and http://teaintheancientworld.blogspot.jp ... ative.html for the often avoided discussion of the stark differences between relative and absolute humidity.
As for myself, I live in southern Japan and store my sheng and shu separately in a glass fronted dish cabinet. With the sliding glass doors closed, it's sealed enough to preserve a microclimate without an extreme amount of air exchange. Humidity here drops pretty low in the winter, (40-50% at around 10°C) and all my cakes are entering into hibernation as of now. In the rainy season and warmer months, my indoor humidity hovers between 60-80% at an average of 20°C. They're alive and actively fermenting at an approximation to Kunming dry storage about 6 months of the year. Could be faster for my tastes, but I can't be bothered to put together something more involved...