1.) Your hides need to be identical.
2.) I would ditch the light and use a under tank heater (uth) WITH a thermostat. Paste this
into your browser for a reliable, cheap thermostat. Under Tank Heaters can get
extremely hot and burn your snake if not regulated. Place the UTH under the hide on
the hot side of the tank.
http://www.amazon.com/Hydrofarm-MTPR...t/dp/B000NZZG3
S/ref=sr_1_1?ie=UTF8&qid=1320845955&sr=8-1
3.) To get the humidity up, you can do several things. If you have a petco or similar store close by, you can buy some sphagnum moss to wet down and put into the enclosure. Personally, I got a spray bottle from walmart for $1 and spray down the bedding a little bit (not soaking). You will lose all your humidity out the screen top, so you can cover 60% of the top with foil to help keep humidity in. Personally, I cover 60% of the top with a wet towel, and then place another towel on top of that one and my humidity stays at 55-60.
If your house gets cold like mine does, a UTH isn't enough to keep up the ambient temps up. So you may have to use a light on top, but again. 85 ambient temps sound okay to me though, as long as you have that UTH set on 90-92 with the thermostat.
I hoped this helped a little and congrats on the snake!