I grow Cacti and Succulents and Orchids during the indoor season here in NJ in the same greenhouse. There are Vandas, which need to be watered plenty, a couple of feet away from them, no problem.
I simply take advantage of the mini climates within a 12 x 20 feet greenhouse - sunny shelves against the house wall and some South- facing sunny top shelves work well for Stapeliads, Haworthias, Pachypodiums, Gasterias, small Cacti and such.
The rest of the greenhouse is populated with lots of different Orchids and two 40 Gallon fish tanks. I water the Orchids pretty much every day, and only direct a gentle quick spray perhaps once a week into the C&S direction, without ever soaking them. Works for me!
I should mention my greenhouse has a glass ceiling and the conditions are very bright, I also have a good fan going and during the heating season, the air from the house also circulates through the greenhouse.
What I am trying to tell you is that some humidity is really not a problem growing C&S.
