Nice information for future reference. Always good to have experienced insights.Your best bet is to call either reptilesexpress or shipyourreptiles and ask for an appropriate box for size and weight of your torts. The Kitsap are cheap at shipyourreptiles and you dont need an account. The kit has the cotton bags to put the tort in so they can't try and dig out of the box. They also include hot and cold packs incase you need them and a label indicating what is in the box.
Either place should be able to walk you thru what you need to do.