Doing the inward press at the beginning of the swing will cause the left hand to twist so the inward move must happen after the wrists are sealed then the inward press begins and produces a really nice shot. Very crisp at impact and add the V pressure as discussed below will result in a splendid shotl
The right thumb and forefinger are held tightly by the meat of the thumb and forefinger at the tip of the V. You'll find that the muscles - tendons used by the right thumb will extend to the wrist. You will feel the pressure. At the moment the backswing starts it's ARC (Path) the same thumb muscles-tendons press inward forcing the right thumb to stay down and pressure must be kept both on the V and inward press. This feeling never stops and as you get stronger with it you will see an amazing controlled shot.
Bobby Jones and other great swingshttp://www.boumphrey.com/swings/bobbyjones/index.htm