Hi Gregor,
Sorry about hte late reply, but i guess Daniel's update answered soem of your questions. I grow i pute moss with some styrofoam as drainage. I grow Disa and in hte summer the Pleione that grow in live moss is in hte water basin with the Disa, standing with their feet in circulating water. It is correct that too much fertiliser damage the moss, but as Disa is even more intollerant to excessive amounts of salts, i keep a low but constant level of dissolved fertiliser in hte water, approxiamately 100 microsiemins. The bulbs became large, so i don't see that as a con. I've planted forrestii and limprictii in live moss along with the humilis from last year and will watch how it goes. I efinately see a potential with more plants, if i can find hte room for it. This methode was after all mainly meant for my Disa.
