I personally would not let any ambient temps in any enclosure fall below 78F. I would not let hot spot surface temperature exceed 92F. Surface temperature cannot substitute for ambient. Given that you are fighting a night time temperature of 63F ambient--that is quite a battle.
Currently with an ambient of 71F inside the enclosure the snake would be breathing 'cold' air every night which it will either adapt or succumb to over time. In your case since you are using a ExoTerra 36x18x24 with a female ball python I would not bother with a gradient as the snake gets larger the enclosure gets tighter: I would target ideal conditions instead. I would use two ceramic heat emitters same wattage on the top symmetrically placed and linked to a proportional thermostat. The thermostat would be configured so that the heaters prevent any point in the enclosure from falling below 78F. If you do this: I would put a deep heavy water bowl beneath each heat emitter to release humidity and prevent the setup from turning into a desert. The difference in temps between the interior/exterior of the habitat will most likely result in condensation and it would be worth insulating the exterior walls to limit this.
As for size of enclosure everyone has their own opinion, by mine: 36x18x24 (depending upon decoration) will be large enough for a small adult female, cozy for a medium-size adult female (assuming you use vertical space), and with just water bowls, climbing stick, and no decoration it may/may not be suitable for larger females (x=diameter vs. length).
Reply With Quote