Anyone successfully use VDOT method to train for 5k?

Sorry for the specific question, but I am curious about its effectiveness. I also have a few questions... I am an advanced runner, but by no means beyond improvement. My PR is 21:45ish (I was puking, not sure of exact seconds) pre baby by a few years and I really want to capture my former time. I have my distance pace and 440 pace down pat, but I am struggling with tempo workouts.