I see why Nate Silver of FiveThirtyEight is so popular these days. Check out his election day guide at the New York Times. He breaks down key races into categories that will indicate how well (or not) the GOP is doing relative to projections. For us in Georgia here what he says:
An Austin Scott victory puts the GOP in the 0 – 39 pickup category. A victory by Mike Keown pushes the GOP into the 40 – 59 pickup category and a Ray McKinney victory in the 12th pushes the GOP into the 60+ pickup category.