I have a glass tank and heating is never a problem as there are many options...my corn snake is happily living in that...

i have a new ball python since 2 days and she has been living at 76F warm temperature which i know is not good enough...

My questions:
1. I have her in a Rubbermaid #2221 - what heating mat/pad should i use?
2. Is it mandatory to have a thermostat ? if yes, any recommendations?
3. How should the set up be? As in, do i need some space between the heat mat and the bottom of the container? etc...

pls help
thanks

Kumar
1 corn 1 BP