If the UTH is properly regulated with a thermostat then it doesn't matter whether or not the animal can come in contact with the glass because the thermostat makes sure it's not too hot. Those who use paper often have snakes that crawl underneath it. Those with loose substrate have snakes that push it out of the way to get to the heat. Just make sure the hotspot is 88-92 and you're good to go. And yeah, ditch the cage carpet.
