Right off the bat

In the beginning of your delivery, coming out of leg lift, what do you want to do? Shift all momentum ( Trevor Bauer - UCLA Bruins Baseball | Greg Davis Sports Photography ) and get back leg linear like that, or do you want to sit in your back leg ( https://i.ytimg.com/vi/-gR6u-nAMII/hqdefault.jpg ) and then drive and rotate hips? I can’t seem to find a happy medium or even really understand how you can get your momentum shifted and then sit hard and load your back leg. Any input is appreciated