For riding on level surface one should strive for high cadence. However, what is the best solution when descending over rough terrain?

On one hand, because the legs are better suspension when the muscles are relaxed i.e. not pedaling, one could make a point for difficult gears. That way, with only a short 1/4 rotation of the pedals close to horizontal position, one can generate acceleration, then quickly return to horizontal position for the next obstacle.

On the other hand, because easy gears make it possible to rapidly rotate the pedals backwards OR forwards, easy gears could be beneficial, providing move agility to avoiding pedal strike.

Are there some guidelines, wisdom or tips of thumb about downhill gearing?