you should hardly see a difference, I mean recessed or not, the heat is going to be closer to the ridges, but the difference is so miniscule that I doubt a heat gun would even pick it up. Even if it does, being recessed is not going to change it. most care sheets give you a range of 90-94 for the hot spot (for ball pythons), just stick to that and you can't go wrong. however not having wear and tear is a plus, however that same benefit can come from back heating.