My daughter is in bad need of an effective change up. Sometimes she has a backhand flip that is inconsistent, and doesn’t seem to grasp the release for a push/horseshoe change. She is a student for about a year with a Tincher pitching coach, and the coach is reluctant to teach a change u til she has mastery of all her mechanics. Objectively, she is about 80% there. In your experience what is the best change to throw and some simple cues to have her be effective. Thanks in advance.