Hmm my first response didn't post. Tegus act like monitors in a lot of ways. I had a nice red tegu that passed away in my fire. They do very well when settup like monitors. They will consume a lot of dirt with food and do the ground and pound method. They will also do a death roll like an alligator (mine only did it once but other report it to be more common). My buddy had one for a year that only made it to 15inches, on peat moss, and basking spot around 105. In 6 months in my care (setup like a monitor) it double it's like and almost doubled it's weight. 130 basking spot, sandy dirt, whole food, mice, roaches, etc.
Peat moss is okay but actually will dry out really quickly if it's only 1-3 inches. Gets dusty and doesn't hold a burrow very well unless it's pretty wet. Cypress sucks for burrowing species (to many sharp ends). Sandy soil with some leaves on top is the best