I do mist but usually when they are going into shed, hope the extra water bowl etc helps you out! I just bought a plastic cat bowl (about 4 or 5 inches diameter) and added that, it helped clear up some of the humidity issues with rearranging the viv.
I have my others in tubs and haven't found the humidity issue with the tubs, you tank looks like a lovely set up though so hope you get the humidity sorted!