Getting 6-8 hours sleep is the key, I think wake up times should be more dependent on what you want to get done and when you have the chance to do so.

For example here I am at the gym at 05:30 already, but it’s mostly because my young daughter and wife are still asleep so it’s a more reliable bet to get in here as opposed to later on when everyone wakes up. And I just don’t have the motivation to go many days at night after a long days work :)