Hi, each map has a combination of 'inland', 'costal' and 'off-shore' water areas. The wave-height setting is relative to these areas.
i.e. you cannot have much more than a ripple in 'inland' waters regardless of the wave-height setting.
To get good waves max out the wave-height and choose a map with large 'off-shore' water areas.
Marseille is a good example, the further out you get from the port the higher the waves are.
Hope this helps your understanding of how SSE treats waves.