Paphiopedilum's proper medium

[Sinister]

I've heard that they are terrestrial I've heard they are epiphytic. I ordered one and it came in a fine mix of bark but the pot was too small. So I repotted in a generic bark solution. But recently it has dawned on me that the bark solution doesn't retain enough moisture. I have blonde sphagnum at my disposal but I'm reticent about using it until I hear it's okay.

If it helps, this is a mottled-leaf hybrid.

-Sin