To select the optimum shaft for you, use a pga pro to get fit. Today with all the software, trackman and others devices, it is a scientific experience.
Long time ago, we were using, trajectories and feeling to select shaft. With modern science there is a lot of factors to take care in the equation.
Some factors are: shaft weights, shafts flex, bending point, optimum trajectory, swing speed, tempo, feel, dispersion, distance etc..
Without a competent person to help, it is almost impossible to a a shaft optimized for a specific golfer.