Don’t feel like you need to confine yourself to even intervals, ex 200s, 400s, 600s, 800s. Try 500s at mile pace first, try 700s. I’m no detective, but by the name I would say look at the Daniels book sitting on your floor and see what he recommends for that type of intensity. That’s a rep, not an interval, and 800m reps at mile pace can be very demanding. If you plan on finishing more than 2 of them, don’t run equal rest to work bout, bump the rest up.