Nice session Mark! IMO you probably don't need to do more reps or do them faster going forward - as you improve you could just cut down on the rest time until you can hit your targets w/ say 3-min rests. (100m slow jog out and then return)2:40 per 800m is about the 5k pace you're shooting for at 16:3x, so eventually this could turn into a 5k pace type session and 6x800 would give you almost 5k total volume.In the fall when I'm doing my base training, I often do 5 x 1000m @ 5k pace w/ 60-90 second static rests between. It helps my aerobic fitness tremendously. (however this is current 5k pace, not target 5k pace)Anyway, really nice session.