mate in the IWS DWC the flood n drain is just to mix the solution to keep it more even. at first just once a day, id only do it max 3 times !
i dont have one by the way but have looked at em. just remember its dwc not flood n drain. heavy idea for a system though just make sure you use cannazyme or similar cause one plants root disease can spread in that system. every system has probs though and you have a good one !
iws customer service is pretty good and they got some good information.
good luck let us know how you go