i find strap leaved vandas cannot handle the california sun at all, very bright light, but not direct sun. it is also very hard to keep them watered enough... you probably have more humidity though. my cattleya relatives (mostly encyclias) can take much more light. i am in the process of transferring all my vandas to pots. the baskets without any media were making them look like raisins. in a south or maybe western window they can do ok if shaded/lit enough. but when you move them around they do go into shock, where they just don't grow all all, for a few months sometimes. once you find a spot they like, just leave them there and never move them.