Actually I realized that I mixed up our regular 4X 1600M, 400M jog (avg. 4:55-5:00) and the session I did a week & a half from the first important race (4X 1600M 4:40 avg. with 800M jog) which I only did a couple of times ever.
Never tried what the OP is attempting though and just gave an example of how I would structure it if it were me.