If the rooms air temp is 85 I would turn the hotspots off.
Why and how is the room air temp at 85? 78-80 is just fine and your snakes will he fine at that temp without a hotspot.
I love herpstats and they ship quick. I have had them arrive in two days before. They also make tstats that can control 1, 2, or 4 separate devices.
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You can use many different things to cover a portion of the screen. 45% is not that bad though and a good daily mist should be all you need. Also using cypress mulch will help hold humidity.
Tell us more about your setup so we can better help you. Pics would really help.