I have 2 oncidiums i can say less light than vandas more light than phals that is my scale. vandas are at the corner of the window and oncidiums are cross the window facing to window they have lights but not direct sun light and i read that you should change the place almost every 6 months they dont like to stay at the same place whole year before spike more warm and sunny environment and during spike little bit less sun what i learned from my google searches. And oncidiums they do love water during spike and blooming i was watering almost every day and and sprayed water to leaves. I suggest you to find a deep plate or bowl put some rocks in it so basicly u gonna have a home made humidity tray. They will need it because i was tired of spraying water mines roots were out of pots and i had to sprayed them almost every 2 hrs because they were getting too try to quick.