We have a UTH centered under the warm side hide with the rheostat theromstat nestled in the substrate at one end of the warm side hide, set to 92 (controlling both the warm side UTH and heat emitter). Ambient air temperature is roughly 80, surface substrate temp in the warm hide is about 90 (via IR temp gun), low 70's on the cool side.

We have another UTH on the cool side, but we haven't purchased another rheostat to control the belly temp over there so it's not turned on, as it seems like our temps are okay. But please, we'd love to hear any advice you more experienced folks have for us!