I feel like maybe with humidity at 90%, you probably don't even need to water 2x a week, ya know? That might be even overdoing it...I'd say try 1x a week. Things don't really dry out at all with humidity at 90%, and you do need that just a little bit to prevent rot.
I'm sure you may have mentioned this in a prior post, but is the air moving in there? You probably have fans up in the top, right?
I forgot to mention, you've got a great list of plants there! I myself pick up a Sedirea japonica a few days ago at the orchid show; its mounted on a a small piece of cork and I just love it :-) Good choices!!