I use a glass tank set up and to keep the humidity in a good range i covered most of the screen with aluminum foil. It help a lot. I only need to mist once a week or so.

As for the uth. with the accurite thermometer it is better if you attach the probe (outside end) inside the tank below the substrate over the uth. then regulate from there. you would attach the thermostat probe to the underside of the uth outside of the tank.

Good luck post some pics when you get a chance.