The gradient is fine. *0 cool side 90 on the hot side is perfect. I might suggest that the hides be positioned over the hot spot and over the cool spot respectively. There can be comments that the hides should be the same or at least similar but if the snake is using both and regulating it is a moot point.

The size is fine big but fine, there are a lot of arguments over size but a well set up enclosure is fine for any ball python. Is your snake feeding ok? If it is the set up is good if not I'd add more plants that over hang the hides some so it is more 'close'

I have always followed that the minimum size is the snakes length should not exceed the circumference. Personally I try to follow 1/2 the circumference. The answer is from the snake itself if your snake is feeding, hiding during the day, and is inquisitive at night. As well as thermoregulating there is no problem, if not then checking all the aspects of husbandry is required size of the enclosure is just one aspect.