I have three phalaenopsis on tree fern mounts. I used tree fern because it holds more moisture than cork or wood. I placed some sphagnum between the roots and the mount. Don't put sphagnum over the top of the roots, only between the roots and the mount. If you use a tree fern plaque, you can drill a couple holes to put the ties trough. The same is true of a clay saucer. You can drill some holes to attach the plant and the hanger. I water them every day. I've never left them longer than three days without water. I assume you know to mount them upside down. Phalaenopsis grow with their leaves hanging down in nature. I placed mine at about a 90 degree angle to the mount so the leaves droop down but the plant grows out away from the mount itself. I've only had my mounts for a year but the plants seem to grow pretty well and you certainly don't need to worry about root rot. Good luck.
Thank you so much. And HEY!!! First time for everything. The flowers have started to fall off but the last bud opened. But anything wrong with my idea I used with the clay saucer.
I have phals mounted on tree fern, driftwood and on palm trees. Here is one on grapevine wood. They all bloom. Just need more water since they dry out faster but variety is the spice of life