So I think I'm being an overly paranoid new mommy but I'm worried about the tank setup I've got for my new little guy who arrived just this morning. He's a month old and is in great shape and even ate a fuzzy rat for me this evening already. However, I'm a little worried that I may not have the temp and humidity being monitored correctly.

Here's the setup: 20 gallon terrarium with screen lid, zoomed uth on right third of tank, giant corner water dish on left third, hiding spot in middle, couple climbing branches. Cypress Mulch substrate about an inch thick all over, small area of moss by water dish. Zoomed thermometer/hydrometer with hydrometer right in middle of tank, thermometer as close to bottom as possible by UTH but still on glass wall above substrate, digital ambient thermometer right above water dish. I've covered half the screen lid with a piece of cardboard to try to keep moisture in. I have a dual heat lamp with a black 75 watt bulb and 100 watt red bulb. My intention was to use red during day and black at night, but I feel like the temps are fluctuating too much and I can't find a happy medium. We keep our house pretty darn cold (AC set at 70 all the time) and its pretty dry here. The humidity has been around 30% even though I've been spraying water 5-6 times a day (I've had the tank set up for over a week to get it consistent before he arrived), and I am a little worried that the thermometers are not accurate enough since I don't have an actual probe set up on the floor where he lays. The two thermometers have been around 82 on cold side and 87 on warm side with both bulbs turned on but I'm terrified that he's either going to get too hot if I leave them on like this all the time or too cold if I try to turn one bulb off. Also, aside from adding foil to the lid, which I'm about to do, any suggestions for avoiding this crazy dryness? Thanks in advance!