I hate to discourage you but Rhynchostylis giganta is one of the slowest growing orchids that exists.
They seldom bloom under 8-10 years old. They are a small plant getting about 10 inch leaf span. They require constant water. I can not grow them without daily water.
As to the other two mentioned Vanda and Ascocenda, Ascocenda bloom younger and easier with less light than Vanda. They usually have smaller flowers whereas the Vanda can have those big 5-6 inch flowers. However, they usually bloom more often that Vanda. Many bloom 2-3 times a year.
There are several color varieties of gigantia. Here are a few
