If you stop to think about it, people dry mount all kinds of orchids, from
Phals to Catts to intergenerics and so on. I have mounted Oncidiums hanging
from Vanda baskets, so they get watered every morning when the Vanda system
comes on. I have Catts hanging under there, too, also mounted.

We have a big Onc. sphacelatum that is in a slat basket which is now about
falling apart. There's no media left in there. That gets watered a little
less, because the pbulbs are large and packed in there, and too much water
would cause rot for sure. When we repot, it will go into another slat
basket.

You just need to adjust watering to accomodate the way you choose to grow
the plant, and your own conditions.

HTH.........

Diana