i repot my bulbo "sometimes", it means every 2/3 years when they are too big. but i don't fertilize them (once or twice a year.i put a bit osmocote)..), and nz sphag looks still nice (but covered by green moss). I don't use pot as i prefer baskets from the garden center (they are larger and not high, perfect to fill with a layer of 5cm of sphag). for slabs i use cork as everybody but sometimes hard wood from blade of terrace. but baskets are just like slabs and when the bulbo is well rooted you can hang then.
but others ways work too.