From my experience growing these guys outdoors, I think N. rajah grows slightly faster than N. villosa. Also, it seems that there are bigger rajahs on the market than villosas. For some reason you can only find like 1-1 1/2" villosas. Seems nobody is growing them out I guess. Since I do grow my guys outdoors, temperature fluctuation is not a big issue for me except for lowlanders I'm adapting to outdoor conditions. As for humidity, both species have done well for me even when the Santa Ana winds kicked up with that 10% humidity factor that occurs in So. Cal. I haven't been to Peter's greenhouse in quite a long time, but I recall him having a few small rajahs there. Can't remember about villosas. Maybe not.