Figured this out today on the 645 music. Go into run (don't start a new run). Long press middle button -> run settings -> data screens -> scroll all the way down to add new screen (+ sign) -> Custom Data -> select the layout you want, then Choose field -> scroll down to Other Fields -> Time of Day. This creates a new running face to scroll through (manually by pushing the up or down button during your run or so think you can set it to auto scroll through your screens in run Settings). Mine also came set up with a clock as one of the default run faces. I’m setting this second in the sort order so I can easily jump to this view while running.