are you sure that is a 400watt HPS?
you should definitley get 1 ounce from each plant (probably more like 2-4) if you veg for 19 more days... you probably don't need to veg more than another 10 days. Don't over water and make sure that those buckets have holes in the bottom.

Careful how much fert you are giving them... the plant in picture 2 seems like it is on the edge...

You may want to clone now...(make babies) then veg for 10 more days and then flower.. that would be the smart thing to do... Next time you can use 1-5 galon pots and fit more plants under the light.

good luck and thanks for the pics..

SMB