There are so many more important things when it comes to signals. IMHO, there are officials who follow the manual perfectly and come off looking very weak/unconvincing. Also, some officials are as quiet as a church mouse when signaling, instead of riding the wave of loud to soft for effect. I don't have perfect/textbook mechanics but I do have great mechanics. Make sense? I work on strong mechanics enough in front of the mirror that I haven't heard anything about stopping the clock in some time.
Something else to think about when working with a young official is the fact that it looks best to use the same hand to stop the clock and point. And, this should be done with the proper hand so your body can remain facing the court. When an official doesn't use the stop-clock mechanic that allows another split second to use the proper hand. The same principles apply for calling a foul/using your "hammer." If you use the 'wrong' hand/arm an official's view is blocked. Not that I really think about mechanics much.
