Okie, I don't know how big the plants need to reach before blooming but I know that very small plants can bloom. When I bought mine 3 years ago, it was a very small and it had already bloomed.
If you grow it with your Vanda it is perfect, even if the specie can bloom with less light than Vanda.
The flowering season is, from what I have seen, begining at the end of spring to early fall.