Missed this reply due to it being buried in requotes. Great input that mirrors my take. Another effective tack is to have the runner run alongside runners with better form in both workouts and easy running and mimicking them at least somewhat, allowing good form to transmit by "osmosis". There was a study years ago about college runners becoming more economical running in groups over four years. I'm convinced that this has been an advantage among E. Africans for decades that pro groups are now trying to mimic with some success.