Overhead to overhead is obviously the most accurate but means nothing if the destination does not allow overhead joins,which many dont.Just think of your field of vision from 2500 feet.All that matters is that you can SEE your destination at the end so that you can adjust for your join.Its no good putting yourself overhead a field only to be told to join right base!!I would say,that as long as you depart in sight of your departure field,then if your plan works out,you should arrive in sight of your arrival field and that,to me,is a good vfr nav.As for a PPL flight test,just do as your instructor says and experiment when you have your licence,as you will find,there are many ways to navigate successfully.. .Ludwig