I usually keep mine at around 95-110 basking and then my tank is so large that I am able to have a temp gradient from around 90 outside the basking light to the mid 70's on the cool side. That way they are able to move around to where they are comfy. Mine will spend a little while in the basking light then move off to the cool side for a while. They usually hang out in the cool side though and that is where the prefer to sleep also. I think the advice Bert gave is good. He has been breeding these for a long time and knows his stuff. You should remember that on this forum we are all posting our own opinion and what we do not saying that we do not know what we are doing butjust it is our opinion. I would have to say listen to the breeder since they have obviously figured out what works to be able to breed in captivity. Just thoughts. Another way to decide is to watch your tegu if it hangs in the warm side all the time increase your temps a little, if it always stays on the cool side decrease your temps a little this is where a good digital thermometer or a temp gun is vital it allows you the ability to see exactly whats going on. Good luck to you with your little guy. If you watch your lizard it will tell you what it needs.

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Beau W.
"There are no athiests in foxholes. It is not an argument against athiesm but rather one against foxholes." James Morrow