Hi Craig, The reason upper body yin poses are held for less time is because there's less fascia in the upper body, and the standard 3-5 minutes can feel like too much time for a lot of people. But if you feel you need more time, you can definitely lengthen the upper body poses to suit your needs, up to 10 minutes each.
Replied on Refreshing Yin Yoga | The 30-Day Yin Yoga Challenge â–¸ Day 19
20 Jan 11:57
We need a good name for that one too! Inchworm? Anteater?