It occurred to me that it's been a year since I recorded what my bow hold looks like, a year of steady focus and (I hope) change. I asked DH to help me record another few clips, so I can take stock and figure out where I'm going from here.
For comparison, this is last year's video:
I am very pleased to see my thumb nicely curving and extending - much better than the locked out version last year. I think my down bow motion is actually a little sloppy - perhaps my finger tips are a little too loose? And I can finally see an up-bow motion that is happening in response to the bow change, rather than because the bow is slipping within my hand in anticipation of the change.
I also suspect the motions are a little exaggerated because I am playing an open string and can thus concentrate on making my bow hand as relaxed as possible. It will be interesting to see what that hand is doing when my left hand and brain are also occupied. Partially to that end, I filmed some "cello trial" clips, since I switched out one loaner cello for the other this week. As I post those you can see my bow hand in action while helping me to decide which cello to keep.