A 20 gauge Parker or Fox, if it fits you, would be an appropriate choice for a Georgia plantation hunt, I would think. As noted above, these will have a bit more drop at heel and comb than newer guns; but you may actually prefer more drop, as do I. It won't beat you death as a game gun, but if you use it a lot for extended rounds of clay games, I suppose it might become noticeable. Best thing to do is handle as many different guns as you can. You'll develop a preference.
Also, you'll want to consider whether or not you want to go with single or double triggers; I always liked double triggers, but they take some getting used to.
The Parkers and Fox guns are probably what drew me into consider something vintage. Good call on handling as many as possible. I probably need to start going to the trap and skeet club more and chatting with people and asking about their shotguns. Perhaps some will let me handle or shoot them. I think I like the mystique, of the double triggers as it seems very old school and traditional, but I often wonder if I'd like it when shooting at game. If I don't master it and it causes me to hesitate or miss on birds, I'd probably regret the decision.
