I realized after reading a bit more about Lucas formula that the size of the reservoir would be irrelevant, i am also inexperienced when it comes to large rdwc systems like this so i really can't advise you on this. Accept to say the 60 gal reservoir sounds right, make sure you have plumping to flush this system if needed & be sure to pick up some renters flood insurance. I have of course watched many of the urban grower episodes/advertisements and i must say that the results are pretty impressive, but you have to keep in mind most of those grow ops are operating under perfect conditions. The whole 2 pounds plus per light sounds great until you realize that pretty much all of the grow ops are using 1k watt lights, so the yield is actually average for a decent experienced grower a pound weighing 448 grams x 2 = 896 just under a gram per watt. I cant speak for Lucas or advanced nutrients personally but what i can say is ANs price for a grow that you might not even harvest would be unacceptable to me. GL with the planning man