Fat tail substrate?

Hey so i'm getting a fat tail pretty soon. More like, as soon as I feel comfortable with the research I'm doing. I have leos, but its not essentially the same thing. So when coming across substrate choices I ran across some that give heat, some that give moisture, some that too easy to clean, and so forth. I'm contemplating the following:

*peat moss = humidity; I think with this substrate I won't have such a "drying out" problem as I might with some substrates. Then again, there are humid hides.
*walnut shells = warmth; My sister and brother both keep many reptiles and they said I could use walnut shells for warmth creation. They also told me they've used the zilla walnut bedding on their afts before without any problems and its great for warmth. I trust them, so I'm considering it, too.
*carpet = clean; Yea carpet is about as clean as it comes, but its also time consuming to wash. You need more than one set of carpet. While one is being cleaned the other needs to replace it in the tank. Seems troublesome and lengthy whereas with regular bedding you can just take out sections.

I'm contemplating these three. Any opinions.