See here for a somewhat unrefined but interesting view of the good and not-so-good skips: Possum Trot
and Short Possum
(or look for the "skip analysis" link above the splits tables)
The main non-obvious thing to know is that normal/normalized means the time savings is adjusted to cancel out differences in overall racing speed, so you can compare the merits of skips more or less directly between fast and slow runners.
Of course, some people like to skip early, late, or otherwise for various strategic reasons, so time is not the only factor, just the easiest to show.