Really, seriously you should follow that tutorial Dr Del linked to as closely as possible.
Covering the top of your tank with tin foil will help with the humidity.
Yes, a thermostat will work with your UTH.
Get your thermostat first (I recommend this one as a cheap, reliable option). THEN move your UTH to the bottom, where it will be more effective.
Get two tight-fitting, fully enclosed hides (such as these)... one log isn't really that great.