I recommend the 2 day required TTT/NA class be 10 hours over 2 days and the refresher class be 5 hours in one day.  (It is listed as 12 hr and 6 hr).   In my experience over the last 6 years, the content can be covered in this amount of time.  Keeping the class "user friendly" is important for those that commute an hour or two to fulfill this requirement. Thank You!