[Mathew]

Swingers really have to control that clubface as it whirls out. As your release swivel goes into its hinge action, it is too easy to over roll or under roll unless monitored. You have to know where you are going to be at impact.....

Johnny Miller on a show I watched via streaming the golf channel, said Jack Nicklaus pulled him aside and asked him what he was working on when he was at the top of his game and he told him he concentrated on his hands and how they were positioned at impact and how he didn't want them here 'turned' or there 'rolled' but just here - and he showed some beautiful flying wedges with the hands vertical to the ground.

Homer Kelley wrote somewhere in the book (roughly paraphrasing) - Program the intended impact hand location no later than the top and concentrate on that and not the means of getting there...