I have grown other Vandas from the flask - the broad-leaved hybrids and they are definitely very different from anything else. In compost, they just stood still, for years ... Eventually I went to Thailand , bought a lot of stuff from one of the big nurseries and asked to see their seedlings department. I found that they stand the seedlings upright, one against the next,all the same size and put them in a wire basket - like a seedling tray, but made of wire netting. Then they spray them, three times a day.. I came home, moved my seedlings to similar conditions, and after a couple of months I was able to take the bigger ones out, and move them into another tray,so as to keep plantlets of similar size in each basket, and so on . Eventually I flowered the first one about 4 years after I had started that procedure. Not fast by Thailand standards, but pretty fast for any orchid by UK standards.
May give you some ideas ?