I've had lessons from Led, Ballard, Gary Smith, Paul Moran, Sorrell, Robert Baker to name a few popular ones ...To me Ballard, Sorrell, "SliceFixer", and TGM are all different methods to get the job done...One method says your head moves 18 inches to left and is a fault if your head fixates at any point..And another says your head must remain fixed throughout most of the swing...I see a style difference as hitting versus swinging in TGM...Whether hitting or swinging is your style, you must keep your head fixed/FLV or the machine won't work too well..