To give you some perspective. I have two T8's stacked on top of each other. My house on average is about 72-73F and about 45-50% humidity (South Carolina). I only use the 12"x12" Flexwatt for the hot side, a fluorescent light and a large water bowel in each cage. My temperatures are 89-90 over the UTD and about 82-83 on the opposite side, with my Herpstat 2 set to about ~103F. My humidity sits at about 62-65% with no spraying or misting machines at all. The only time I spray is during shed and I do that once a day which keeps the humidity at ~75%.
If you are looking for better ambient temperature control I would look into RHP instead of using UTH along the entire tank. It would be more efficient and reliable.