So i wen shopping tonight for the snake we currently have. I bought an UTH, a Ranco thermostat, 2 accurite thermometer/hydgrometer, day bulb, heat lamp (its the infared kind, the ceramic ones were 40 bucks so i wanted to see if I could fine them cheaper), repticarpet, bedding, new water dish. I also made 2 hides that are next to identical, I also got some fake leaves and what not to make it look nice.

My questions:
Am I good with only one UTH? I have a 20 gallon long. Or do i need two?
I think I pretty much understand about putting the UTH on the tank with the thermostat and foil and what not. We are also going to foil the top of the tank (well 3/4 of it).

What can I use to wipe out the inside of the tank?

What is a good sealant for wood pieces going into the tank?

Is there anything else that i need that i havent gotten or am I not on the right track? I want to make sure I set it up right. I am also getting the other snake on monday so i will have to set up a tank for her as well. any input would be great!