I grow mine just moist, and in a very airy mix of perlite, sharp sand and vermiculite (no peat). Its important to get air around the roots, otherwise they rot. Although I use tray watering during the active growth period, the looseness of the medium allows the roots to breathe. If the plant is not in active growth, I cut back the moisture. I do not mist my plants: they dislike wet leaves. Humidity is provided by an ultrasonic humidifier, a very very fine mist, not enough to wet the leaves, and this only in the morning. I find the Mexican species are better treated as succulents most of the time, not to wet, good light and high humidity.