I don't know what folks advise, but I had a "rescued" Super Giant shipped to me from Central FL on Monday, which had a high of 97F. The sender used Fed-Ex, taking it to a location herself, and packed it well. It arrived on Tuesday morning at my office. She included moist, but not sopping, paper towels in a plastic container with plenty of air holes. Then a layer of crumpled newspaper. Then a cold pack that didn't have direct contact with the plastic container housing the gecko. Finally, the exterior was a cardboard box of adequate size, which she also perforated to provide air holes. She wrote "HARMLESS LIVE GECKO" and "FRAGILE" on every side of the box. She then took it to Fed-Ex and they did their part. He arrived safely.