To achieve the 5-6x200m for a developing quarter miler you will probably have to go through a progression like:
3x200m
2x200m [5min] 2x200m
3x200m [5min] 2x200m
3x200m [5min] 3x200m
5x200m
6x200m
Doing this session once a week it usually takes 2 sessions at each progression to achieve target times. Depending on the athlete’s endurance qualities they may need more than 5min between sets.