Tips on keeping savanna monitors??

That UTH heater will be fine for now.
You are going to want to keep it outside the tank with proper airflow between the pad and the surface it is on.
I also would recomend a rheostat or thermostat to prevent burns.

Does anyone here use a heated pig blanket??

Heres some useful info for the both of you, get a temp gun and get your basking temps up to 130F+ so the monitor can properly digest its food..

Does your 20 gallon tank have a solid top, if not cover it so it will keep the heat and humidity in.
When you make the 8x4x4 (LWH) make sure you waterproof the wood so you will be able to put a good 1.5-2 feet of dirt so your Savannah can burrow and line up a row of 45W or 90W halogen bulbs from lowes or home depot to get the 130F + basking spot
This is from a 90W placed about 12 inches away from the basking spot
http://i476.photobucket.com/albums/r...ryan555010.jpg


Bryan

with a basking spot that high how do you keep the ambient temps proper? and what temp is too high?

You need a temperature gradient in the cage, i have 2 different basking spots in my cage which include 2 bulbs each that the temps range from 135-164F. The monitors will use what they need or want, if its too high they will use it less or hide. If the temps are not warm enough they will sit there for most of the day. Those 3 or 4 bulbs heat the whole cage and i get ambient temps of 80-90F.
Thats why alot of dirt is also important as if they want to get away from the heat they can dig down to cooler temps.


Bryan