In Coach Parrot, the maximal penalyu in passing training speed is 30% for guys 7'2" and above (i.e., where a short trainee would get 1.0 relative passing increase, a tall guy gets 0.7)
For comparison, the penalty to jump range or outside defense for very tall players is 60% (for every 1.0 OD or JR gained by a short guy is just 0.4 for a tall guy).