Mounting Orchids in Dart Vivarium

[drtfr33k16]

First off I want to apologize for this question may have been asked before but I want to make sure all of my questions are answered. I have a 20 gallon vert(vertical) with a space for plants 1 foot wide, 9 inches deep, and 15 inches high. I am looking for an epithytic(sp.) orchid to mount on the wood or background and i cannot have a terrestrial because there is no substrate just water underneath. I can position it to get verrying amounts of water due to the two small driplines in the background and it can be positioned to receive very high to low light. I would really apreciate it if you could give me a list of beginner orchids that fit this criteria and there special requirements. Thank you very much for any input.

PS; It will be a very humid environment and I can but would rather not intsall fans there is a small mesh strip 2 inches hich at the top of the paludarium.

Justin