Bihai,
You could probably get away with either as I have found that with enough humidity, most of these smaller shinglers will attatch themselves to anything and grow. But your best bet would be to have them in soil or perhaps spaghnum moss growing with a totem. The climbers will never get any size to them without some kind of substrate and they do need a little feeding here and there. However, I have found R. pachyphylla growing directly on clay pots in my Greenhouse and have mounted R. cryptantha directly on cork bark.
Michael M.