cage temps

I use a rack system with belly heat. My cage temp is always a few degrees lower than my thermostat setting. I feel like Im constantly tweaking it back and forth and Im never confident that temps are perfect. How do you place your temp prob in the cage? Should I be monitoing directly on the hot spot or the ambient temp around the hot spot?

You should be monitoring both actually. The thermostat temp is monitoring the UTH to make sure that its the proper temp so that you don't burn the belly of your snake.

But ambient temp is something totally different. You should have a temp guage with another probe to monitor the ambient temp in the tank. The thermostat only makes sure that UTH is ok. And im not sure that UTH alone will produce enough heat to make the whole tank hotter without making it dangerous for you snake to lay on.