Here's what we do and have been running pretty darn consistent temps since the addition of our UTHs without all of the other stuff.

Email Rich at Reptile Basics with the tank dimensions. He'll tell you the proper sized UTH. We have 11x11 ultratherms for our 20g tanks. GET A THERMOSTAT!!! Our hyrdrofarms are set at 90 degrees. We attached these with aluminum tape and covered the entire bottom of the UTH with the tape so that the heat would be reflected back into the tank instead of heating the underside of the tank. We double check all of our temps with a laser thermometer just to be sure.

Our room temps before the addition of two snakes sat at 72 degrees.

Okay, we have medium (?) light hoods. They are about the same width as the top of our tanks with 75 watt RED bulbs. Seriously, red is better and don't run as hot to put out the same heat in the tank. Ours are on dimmers so we could dial in our temps.

NOW... cover the open portion of the screened top with a damp hand towel folded in half. We change the towel every other day and re-dampen with hot water every morning.

With these simple things our temps and humidity has been pretty damn consistent with paper towel substrate.