Question about temping

I've read that not only is it important to temp at the same time each morning, it's also important to have at least 4 hours sleep. Which one is MORE important. For example: I usually temp at 6am. Since it's now 2:30am, if I temp at my regular 6 am time, it won't be a full 4 hours. But if I sleep the full 4 hours, it won't be 6 am... Anyone have any advice?