I've found they seem to do really well mixed with peacock moss (selaginella uncinata). The moss supports them and seems to help prevent any stem rot from direct moisture while helping to maintain a humid micro climate around the plant itself. The foliage mix is really nice too with the lush blue/green of the peacock moss and the iridescent veining of the jewel orchids mixed in. I'm basically using this mix along with miniature gesneriads and iridescent Microsorum thailandicum/ M. steerei in most of my current tanks. I really like the mix and think that will be the main plan for the future also, with a few small orchids added to the mix.The key thing to know about orchids is that they are ramblers, you don't plant them IN substrate, you plant them ON. Adding one to a tank? Take a cutting and just toss it in the general area you want it in. Have a whole plant you want to put in? Cut off most of the roots, and toss it in the general area you want it in... it will get busy growing new roots in it's new home ASAP.
I'm lazy, and just toss my jewels in after trimming roots and see how they do. Haven't killed any yet No fancy substrates needed!