I'm also in Georgia, and was told by my father-in-law that I should only use one brood box. Then that I should use an excluder and place honey supers above that. He said that's how he used to do it, and that this is how all commercial beekeepers do it.
I shouldn't argue with an elder. :) But I do. I learned most of my beekeeping from reading on the internet, through several sites. I started my hives with one brood box, then added another, because this is what I read you should do. (I'm sorta trying to say, I don't know the RIGHT answer, but maybe things have changed.) But my father-in-law still insists I'm doing things wrong, and allowing my hive to get too big where it might swarm.
My thoughts on the matter....... Isn't a big hive good? larger numbers means it's stronger and better able to do the work needed, right? More bees, more production, more honey. Plus, a larger hive going into winter.
Anyway, I did two brood boxes because this is what I read I should do, and what I saw pictures of hives having - two large supers, then honey supers.
Now for what to expect as far as growth for this year. Like I said, I started last year, in the summer. I did get a very late start - about as late as it gets (June 27th). The bees did fine on building up to a strong two deep supers. I tried adding a third super on mid-September because they seemed ready for it. I had grand ideas of getting loads of honey in a fall harvest. :) NOT! They wouldn't even start building comb up there. I guess they had enough to do, and enough space, in just the two supers.
I did manage to get some honey at the end of winter though. I looked in on them at the end of December, and they'd hardly touched the honey stores, so I took two frames. Then at the begining of Febuary I took two more frames. It still left them with honey, and things were begining to bloom anyway.
One last bit of advice. If I had known back in the fall what I know now, I would have prepared myself. My hive grew really large by Febuary, and ended up swarming on March 15th. If I'd been smart, I would have bought more frames and built more supers over the fall and winter. I would have split the hive during the first nice week in Febuary, with a second empty brood box above. Instead - I lost the swarm and split the hive at the end of March. Then I lost a month of production and brood rearing because there apparantly wasn't any brood young enough to be made into a queen in one of the hives (one did have LUCKILY one good queen cell that hatched). I did goof in lots of ways.
So my advice - stay one step ahead of the bees, and be ready for a huge growth as soon as weather warms (in Georgia that can be January).
Sorry for the long post, but the "one super" - "two super" thing is sort of a sore spot for me. :) Even though I've had the bees for a year, my father-in-law still insists I'm doing all wrong by letting the bees raise brood in two deep supers. And I'd say between the two hives they've made 150-200 pounds of honey so far this year. I've only taken about 65 pounds of it, since the rest was on frames that were half brood/half honey.