I'd add that many beekeepers only run "1" brood box and manage accordingly. As the nectar flow begins just slap a queen excluder on and a honey super (I use mediums). Once they start storing nectar in the honey supers you can pull the queen excluder. I install a QE initially to keep the queen in the brood box. If you find that your (1) brood box is getting to strong, you can always do a split, start a NUC, or give weaker hives a frame or 2 from it. So... don't think that you have to run 2 deeps.