Ball python shipping question

I am getting ready to ship our first ball python out on Monday and just curious what temperature do you put the heat pack in and what temperature do you put the cold pack in.

Meaning if X or below I put the heat pad in
If X or higher i put a cold pack in

If anyone has an answer to this I would greatly appreciate it since this package is to leave tomorrow and I want everything to go smoothly

Hope this helps.
http://www.reptilesexpress.com/packing_guidelines.aspx