I think swing speed and strength are variables to consider and also kickpoint

More speed you swing with and torque you generate the stiffer the shaft you want. I think if you generate a lot of club head speed and have a lite flex the club will twist and you will get inconsistent results rather than a predominant draw or fade .

Kickpoint is where the shaft bends. The lower the kickpoint the higher the ball flight. They usually come w/ low/ mid and high kickpoint.