-- 5 x 100 @ 1:30 easy
-- 200 kick
-- 12 x 100 pull @ 1:30 aerobic pace
The trick is to swim an even main set, holding my heart rate at right around 140 or 145 for the entire set. That should translate to something on the order of 1:17/100, but we'll see how it goes.
The nice thing about pulling is that you can work your muscles a little harder without committing heart rate reserve. This is because you're wearing a pull-buoy, which has an effect similar to that of wearing a wetsuit.