mounting bulbophylum

[orchid_guy]

I have grown orchids for a while now, but usually stuck to clay pots. I want to start mounting some of my Bulbophylums because some of them tend to spread out due to the rhyzomes. I will mount to cork bark with sphagnum moss. If mounted, does every part of the plant and every pseudobulb/root system have to be in contact with the moss (for most contact with moisture)? Or can part of the plant - the outermost growth hang free? Does this impact the ability to accept water, etc?