The brand of UHT matters for a start some are regulated to a lower temp (but the regulator can fail so a thermostat is still advisable).
Since you don't plan on keeping the tank set-up just cover 2/3 to 3/4 of it with a damp towel to help keep humidity up. Keep this well away from the heat lamps.
Check out the care sheet they have here it is full of very helpful information.
Congrats on acquiring your snake, I hope you enjoy it for years to come.