Want to maximize chest recruitment? Do 5-angle flyes.
Various angles of adduction are necessary to maximally recruit the pecs from the clavicle to the sternum. This exercise will hit most of them to stimulate new growth.
As you fatigue in one position, adjust the angle to a new position: high, mid, low or someone between those angles. You can even go back to a previous angle. This also allows you to extend the time under tension, one of the key components of hypertrophy training.
This six-week program breaks some of the currently accepted rules for workout volume and duration. That's why you'll do more than 20 sets per workout and you'll train for 60 to 75 minutes.