I know most of the OBers will say to use the Sphag and bag-method to grow roots.
But still, i have had good results by just sitting the bulbs in S/H, and provide higher humidity by putting a bag over the pot, cut a hole in the bag for air-sirculation, placing the pot out of brigth light, and keep it in a warmer place... Another way of S.a.B, i guess.
I have just gotten new roots to a rootless, little bulb on my Cambria. The motherplant is doing great, are growing two spikes at the time, but this little bulb lost its roots due to rot since it were burried down in leca (when i was away in holiday, the hole pot fell down, and the chid-sitter put it back, burring the smalest bulb).
After cleaning it from rot, i just placed it back in the pot with the rest, and put a bag over it. Now its started to grow roots again, after just two weeks.
But this chid has been growing in S/H the last six months, i dont know if thats a point to it, too...?
But, S/H-culture is not usually a miracle-cure for dying chids... Its just another way of growing, that some find better, and some chids prefer...