Best way to heat a 37 tall dumpy enclosure?

[Theodore Tibbitts]

So I set up my dumpy enclosure about a week ago. I'm currently heating it with a strip of heat cable taped to the top back, as I read heating lamps tend to dry things out too much. The temperature against the back wall is 77-80 during the day and 76-78 at night, whereas the temperature in the middle of the tank is more like 72-74 during the day and 68-70 at night. Is this too cool, or just right? I've read 75-85 is good, but I am concerned they don't get much of the heat since it is radiating only off the top half of the back of the enclosure. I'm contemplating buying a small basking lamp just to get it warmer in places other than the back wall; I think most of the heat is quickly escaping out of the screen top, but if I cover it the humidity quickly hits 100% due to my water feature, plus I've read Dumpies need good aeration.

[Valentine Pirate]

Have you tried a lower wattage ceramic heat emitter? I hear they aren't as harsh as lights on humidity and it can create a heat gradient from top to bottom (or to one side, if the enclosure is wide enough)