UTH placement

I'm going to be getting a baby Sumatran Blood very soon and I'm not sure if I'll be using a UTH yet. People who keep them in terrariums; I understand they require a thick layer of substrate so do you still keep it(tstat) turned it to 90 knowing the snake may burrow all the way to it? Or is a heat lamp going to be enough? Is it important to heat the substrate?

I personally dont like the lights because they dry out the cages and bloods need humidity. I really dont know the answer to the other question mine are in a climate controlled room