1Preheat oven to 375°F.
Crumble the cornbread and white bread into a very large baking dish or pan (This is the pan you will cook your dressing in, and you need room to stir it while it's cooking). You will have approximately 12 cups of crumbs, perhaps a little more.
In a large skillet, sauté the celery & onion in butter over medium heat until onion is transparent. Combine the sautéed vegetables with the bread crumbs and mix well. Note: The dressing up to this point can be prepared an hour or so in advance.
When you are ready to bake the dressing, add the beaten eggs & chicken stock and stir. (You may need a little more chicken stock -- better if it's too moist than too dry; the uncooked dressing should be a little on the slushy side). Add 2 teaspoons poultry seasoning, 1/2 teaspoon rubbed sage, black pepper, and mix thoroughly.
After baking for 15 minutes or so, stir dressing down from the sides of the pan so that it cooks uniformly. Check the seasonings, taste it. If you don't taste enough sage for your liking, add 1/4 teaspoon or so with a little chicken stock, stir it in, and taste again. Careful, a little sage goes a long way.