I too am planning a DWC setup. From what I have read the way to do this is as follows:
Start your seeds or clones in rockwool cubes, you can use the type with a hole pre-drilled for starting plants. These can be started with the "wick method" type of hydro setup, low light till they take root and a hood if you're doing clones. Once the seedlings are "ready for prime time" you stick the little rockwool cube in the netpot, using the grorocks (or whatever you're putting in there) to fill in the rest of the space. This is far superior when compared to transferring from soil because the shock, if any, to the plants is minimal.
Also, I noted that you say you have drilled 3 holes in the pot, increase this exponentially; make that sucka look like swiss cheeze
Good luck