No kick too
Charles, with your permission, and ss, I took my fins to the pool and tried your rotation and unco drills, good fun.
Then I tried freestyle without kicking, holding my feet still and fins together. I was amazed at how much pressure rotation put on my thighs and how hard it was to resist knee bend and a toe flick. It also lifted my hips too high and made breathing difficult. An illuminating experiment for me.