Here's what I have in my notes, but I could not tell you the source...
Phals, 1000-1500 fc
Oncidiums, Catts & Dends...2000-3000 fc (I think mine get more like 3000-4000 and seem happy)
If anyone has different info, I am all ears.
No idea about cymbidiums...I'd love to hear that one.