Performing a pullover with a cable allows you to place the lats under continuous tension throughout the full range of motion, triggering more muscle growth. I also add a stability ball to the mix because it allows me to position my body in a way that gives me a greater stretch.
Don't do this exercise first on back. Do it after you've got a pump going. Stretching a fully-pumped muscle is a great mechanism for growth.
Use controlled reps. You don't have to count out the tempo, but note in the video that every rep takes a few seconds: a couple of seconds on the lifting or concentric phase, and a couple of seconds on the negative or eccentric phase. Really focus on your lats doing the work and build your mind-muscle connection.