Another advantage of sphagnum as a medium... you can form it into sort of a ball, that will stay in position in a "woven" basket like that. Wouldn't work with bark of course, but sphagnum is the medium of choice for this type of orchid anyway, If you use this approach, maybe best to use nylon cord or similar material - natural fibers like cotton are going to rot pretty fast with all the moisture.
I've never been good with mounted orchids. I have about 30% humidity in the house (in the room where I keep the orchids). I have found better success with a slotted plastic pot and mini-bark chips, and a 2 bowl "semi-hydroponic" situation with small orchids. Right now, I have a seedling tigerinium cattleya, and an immature dendrobium abberans in this treatment and they are doing well and growing.