I used an Emily's Garden before and the plants will be a bit crowded, unless you are growing shorties. The tray is 24 in x 16 in and it only holds a total of 2 gal of nutes. I wrote a thread on how to build a bubbler which is nearly identical to Emily's Garden but you can choose the number of net pots and it hold approx 5-6 gal of nute solution.. in other words it is more forgiving since there is more solution.

BUILD YOUR OWN BUBBLER LINK

In the thread above I have 6 net pots, but I only used 4 max, and the 2 empty spots I left in the middle, filled with hydroton to prevent light into the res. It make checking and adjusting the solution a breeze - just lift out a pot, set it on top of the other middle one, adjust and replace.