Wow. very good buy. Coming to care, Vandas require direct sunlight of atleast 3-4 hours. They grow in a windy and high humidity areas in thier natural habitat so no real problems in HongKong.
You should mist the roots daily or even better soak them in a bucket of water every alternate day. You could fertilize them once a week or even twice a week and soak the roots for half an hour or so. care that water does not stagnate on the crown or on the leaf folds.
BTW, Nice grow area. Sure you can hang a few more vanda's in there