Anna, I have great luck mounting orchids on wood, not so much on cork (though others in my same area LOVE cork).
I have tried repeatedly to mount phals, with very little success---one time I put 3 good size, very healthy phals on a slab of wood, 2 died relatively quickly and the third one is still hanging on, but has gotten tiny...to the point where I think if I don't remove it soon and give it a real pot, it will die too.
An idea that struck me...maybe your phal is doing so well BECAUSE of the stocking & sphagnum, which holds more moisture than if it was mounted bare...even if it IS already attached.
When I mount something I usually use spahgnum behind or around the root ball, and so far I've not removed it on anything I've mounted. I will go outside and take some pics of my mounted stuff...maybe it will help or give you some ideas. Although I'm sure my climate is very different from yours...Florida is much more tropical, so maybe what works for me wouldn't work for you...
I hope others chime in here as well!
