In the early 90's I grew nearly all my orchids in well bank rock wool, which was a mix of water absorbent and water repellant rock wool and small pieces of foam sponge, I found it a fantastic medium, though others couldn't get on with it at all. I think this proves there are no miracle answers when it comes to media, it's all about what suits the individual and their particular conditions/ regime. Having said this I don't see why you shouldn't use this inert media to your advantage with cp's ( though pure absorbent rock wool can get VERY wet).