To stay connected to the body's rotational energy, it is very important that the first movement of the hands is not directed toward the pitcher - or inline with the incoming pitch. The batter should keep his hands back and allow the rotation of the body against the lead arm to accelerate the hands. The first movement of the hands will then be propelled more perpendicular to the flight of the incoming ball. This will induce the greatest amount of angular displacement to the bat and propel the hands into the most productive path.
Setting up the drill, you want to have the bucket behind the back foot of the hitter. The purpose is to work on the transfer of weight from the back leg. In order to do that, we cannot simply rotate our back leg while our foot is anchored. This is why this drill is so helpful, the bucket will give you immediate feedback for incorrect or correct weight transfer.
While batting average is a useful tool for measuring a player's ability at the plate, it isn't all-encompassing. For instance, batting average doesn't take into account the number of times a batter reaches base via walks or hit-by-pitches. And it doesn't take into account hit type (with a double, triple or home run being more valuable than a single).