Something I noticed is that your 30 second poses seem to have more flow than the longer timed poses, I would try and look into why that is. maybe it's the lack of time or the lack of care due to the short amount of time spent on the pose so there is less stress. I would try setting up a pose in 30 seconds and then going back and using the rest of the time to refine while keeping the flow of the original sketch/outline. keep it up you're doing amazing!
