The relative speed for each athlete that these are run is what determines if and how much the workout will be lactic acid training. Workout B will allow the runner to run the 200 repeats faster, but there is virtually no aerobic maintenance or development with this work. And if the workout is a true lactic acid shock, it may take upwards of 3 to 5 days for your athletes to truly recover.
I would have this Workout in the afternoon, with a healthy 2mi warmup and 2 mi cool down. If any of the runners are 60 mpw or more, then they would also need an AM run to supplement their mileage for the day.
I would also have a lactate threshold run within a day or two before this workout, so that after the recovery from this speed workout (two days), your runners won't go too long without a quality lactate threshold run. A runner needs a LT run every 2 to 5 days in order to not lose any aerobic ability.
This would be my week:
Thursday - LT run 5 or more miles
Friday - Recovery Run
Saturday - (AM Run for higher mileage kids)
PM Speed workout, Total miles for afternoon session - 6 miles
Sunday - Recovery Run
Monday - Long Run (also, Recovery)
Tuesday - Short LT Run of 2 to 4 miles (5 days since last LT run), possibly followed by some light speed work.
Wednesday - Recovery Run
This schedule will integrate nicely if most of your meets are on Saturday. If you're kids are racing properly (ie going out fast enough), then every meet should be a lactic acid shock (until the last one or two that really count).