Looking for people who use animal plastics and heat panels.

I am waiting on my new T3 to arrive, I am placing a heat panel on the inside. Just wondering if anyone else has a similar setup, and wanted to see if you palce the probe for the thermostat in the probe spot on the bottom of the ap cage, or do you put it on the floor inside. I know the pre-cut probe spot is more for the heat cable that they sell. Just wondering if you do use the pre-cut probe slot, how are your ambient temps?