Okay.... I've had a few minutes to think about wicking the water up versus letting it filter down.
If we agree the object of the exercise is to fill the available space with a vibrant root system then, I am of the opinion that allowing the water to filter down thru the medium promotes a better root system. My reasoning is that the water, will_if applied properly_a more even spread of the moisture throughout the medium, which will result in roots everywhere, with a concentration of them_nowhere.
If, on the other hand, we rely on the hydrophilic_
technical word for wicking of moisture_this requires a supply (pool) of water and, IMHO, offers the best opportunity to incur root rot. Also, since the water has to travel up, there is less chance the upper regions of the medium will achieve proper moisture levels.
All this being said. If you are achieving acceptable results - forget the above.
Phew....see what happens when I take a bong hit.