How does the foot flare affect the loading process?

How much you open the lead foot (that is the flare) changes when rotation ends and when the upward push arrives. The more the lead foot is flared, the longer the rotation lasts, and the later the vertical happens. The squarer the lead foot, the shorter the rotation, and the sooner the vertical happens. Do not copy another player’s flare and then wonder why your vertical is late or early. Set the foot for the timing you actually need.