We usually have pretty low humidity too, but not sure it's as low as yours. We use Matsui's wetting agent in most of our inks and it really helps. We also don't leave the screens flooded (I know sounds counter intuitive) when not printing, but rather make sure we print the ink out of the screens for break etc... seems to work. When we first started printing water base we followed the old recommendations about making sure the screens stayed flooded we found this just didn't work nearly as well as treating them more like plastisol.
Seems to work for us - YMMV. :)
