Last week it seemed everyone was in a group of 1. Lets this week try to get into semi homogeneous groups, even if it means your a second or two fast or slower than your pacing charts indicate.
5-8 X 800 @ 8k pace, 200 rest, do your last one at 5k pace.
Number is dependedant on your weekly mileage and relative experience with track workouts. About 8% of your weekly mileage in intervals of this speed is about right.
5=30 mpw
6-7=40 mpw
7-8 = >5o mpw