I was just looking at the local weather where the whites tree frogs roam wild in australia and it is dropping to 68 degrees at night and mid to low 70s during the day... SO your temp for this time of year in their wild climate is perfect.

The thermastat in the middle should be sufficent. So what I would do to make sure you get the evening and day times temps fluctuating for their local wild environment is leave the small heat pad on...and turn the light off. Monitor for a week and post your results here for day and nighttime and its always good to monitor the local temperatures of north western australia to make sure your getting the proper temps of the time of month.