I finished the drainage system in the orchid room yesterday. This was a long project, as I had to build the trays, 16 of them, design and build out the plumbing system, and make it all work. I watered the plants this morning (which took only about 15 minutes), and everything worked perfectly. It took approximately 5+ gallons of water, of which about 3 gallons drained out (into the white bucket in the lower left). The plan is that the water either remains in the pots, in the humidity trays, or drains out. So far the humidity trays have a little more water than I had planned, but not excessively so. I expect to flush the humidity trays with a bleach (or Physan) solution every month or so.
This should enable the plants to remain in place, which should make them much happier.