We recommend keeping your wrist flex to a minimum to develop a consistent throw. Often times just modifying your grip can help to adjust the dart rotation. Here are several modifications:

Try sliding the index finger of your throwing hand closer to, or farther away from, your middle finger. As the separation between your fingers increases, the rotation decreases. Alternatively, as the separation decreases, the rotation increases.

Grip the dart closer to or farther from the end of the dart. As your grip moves closer to the end of the dart, the rotation increases.

Grip the dart closer to the tips of your fingers. This will increase the rotation of the dart.

Changing the distance you lean toward the board, your grip, the speed of your throw, the flex in your wrist, and your follow through, all effect the darts rotation. Keeping these constant will help you to achieve a more consistent and accurate throw.