Substrate Question

That is exactly true. If a lizard (or really any reptile. I'm just more experienced with lizards) is not properly heated, they cannot digest as fast, if at all. It's almost like if we tried eating without stomach acid. It just wouldn't work.

if you get into monitor lizards, they need crazy high basking spots (My savs bask comfortably at 146-150.) Tons of people go onto forums freaking out cuz they ate a mouthful of dirt. As long as they are heated properly, there is almost no risk of impaction. My lizards all like rolling their food in the dirt and mud. And my savs love drinking up mud puddles while I spray the tank(And they have a big water tub too)

What methods do you use to get the spot that high?

3 flood lights (45 watts, par 38) About a foot from the basking spot. I use flood lights for almost all my basking spots. They are very efficient compared to spot bulbs. They make a far better gradient.