Congrats on the new boa. Im adding one to my collection this week. It'll be my first boa too so we can learn together. If you're using a uth I'd place the t-stat probe between the uth and the bottom outside of the enclosure. Your warm hide should go directly over that spot on the inside. I usually have to set my thermostat at 92-94 to get an interior surface temperature hot spot of 86-88.