Do you do any instruction or have any focus on what the knob of the bat is doing? Or do you focus/teach what the hands or bat head is doing? What do you look for on each?
Knob pointed at catcher at toe touch as a general check point. Hands staying more centered and not pushing back into an armbar and getting stuck. The bat head being whipped around the hand pivot. Feeling of bat lag and effortless speed. Loose top hand, specially the index finger.