I grow them in clay pots. Small seedling-sized ones are in a handfull of chc. Large ones have their roots curled in the pot with some small plastic net pots in between and then topped with thin layer of sphagnum. I water when sphagnum gets crusty dry, usually every 2-3 days(depending on the amount of sun).
Every watering I add 1/4 strength of 20-20-20 ferts.
Just recently started to add seaweed extract to the watering mixture.
I tried many methods with vandas, including glass vases, but this one seems to be working best in my conditions, easier to handle and less job watering them.