So, I've done a lot of research, but I haven't been able to find a consistent answer to this.

Where exactly do you measure ambient temperatures? Cool side? Middle?

The most common range I've found is 78 to 80 degrees, but is this meant to represent the entire temperature gradient in the tank? It seems kinda small for that.

I don't have my ball python yet, so there's no risk to animal welfare. Right now, my temps have stabilized at 80 degrees on the hot side and 75 on the cool side. Unfortunately, I don't have a surface temps yet, but the temperature gun should be arriving soon so I can get those. I'm using an UTH for the hot spot/belly heat and a ceramic heat emitter for air temps.

I can guess that ambient temps does not refer to the hot side, but should they be measured in the middle or on the cool side? Or does this depend more on the temperature of the substrate?

Please let me know if any additional information is needed.