Us the results from your lactate threshold. Most people, I set the lactate threshold at 80% and it works well.
You shouldn't ever see your max heart rate. I did the 2 X20 and it set me at 160 (professional tests put me at 159, btw). I never thought I'd see a heart rate of 200. I saw it once. But then again, that day, I saw God too.
In fact, I think I saw the entire Holy Trinity- father, son, AND holy spirit.
Max heart rate is not a number you should ever see (or you shouldn't see it most of the time).