when to drop the rockwool into netpots

i just started 4 new seeds in 1.5 inch rockwool cubes (first time using them) and i am going to try out rubbermaid dwc for the first time.. my seeds are just sprouting and have their first set of true leaves... when should i transfer them over to the netpots with hydroton/ start them on the FF feeding chart? & how low should my res water be from the bottom of the netpots?? im new to the game and i keep smoking away all of the good info i soak up reading rosemans diy thread haha.

I put germed seeds in cubes and directly into netpots and into the dwc system. As for water level and feeding them until roots are in the water, read the link below. If they have a good set of true leaves I would start light nutes right away.