Hello Susan
You know, that is a great question. And once again, it depends!!! 😉
For most students and especially beginners, I like to see them focusing more on keeping their heels up as high as they can. It makes sense that if you can stand up on your toes before you descend into this pose, then you SHOULD be able to keep your heels up as high, as you hips start to come down. So the best course of action for most students is to keep attention on the height of their heels (or the opening through their ankles). Remain vigilant to the slightest movement from this upward position. As soon as the heels start to drop, back out of the pose a tiny bit and then place the weight forward in the feet again by pushing through the ankle.
Once that is handled then the student can bring their attention more fully to the hip position. You are right that the hips should never drop below parallel. I believe that the hips really do have to be marginally higher than the hips as a final position to keep the forces working forward through the ankles.
So both are important, but the hierarchy: is feet before hips.
Namaste
Gabrielle 🙂
