Combine salt and sugar in bowl. Using your fingers, gently loosen skin covering turkey breast and thighs. Rub 4 teaspoons salt mixture under skin of each breast half, 2 teaspoons salt under skin of each leg, and remaining salt mixture into cavity. Tie legs together with kitchen twine. Place turkey on rack set in rimmed baking sheet and refrigerate uncovered for 24 to 48 hours.

At least 30 minutes before roasting turkey, adjust oven rack to lowest position and set baking stone on oven rack. Place roasting pan on baking stone and heat oven to 500 degrees.

Combine 1½ teaspoons oil and baking powder in small bowl. Pat turkey dry with paper towels. Rub oil mixture evenly over turkey. Cover turkey breast with double layer of aluminum foil.

Remove roasting pan from oven. Place remaining 2 tablespoons oil in roasting pan. Place turkey into pan breast side up and return pan to oven. Reduce oven temperature to 425 degrees and cook for 45 minutes.

Remove foil shield; reduce temperature to 325 degrees; and continue to cook until breast registers 160 degrees and thighs register 175 degrees, 1 to 1½ hours.

Using spatula, loosen turkey from roasting pan; transfer to carving board and let rest uncovered for 45 minutes. While turkey rests, use wooden spoon to scrape any browned bits from bottom of roasting pan. Pour pan drippings through fine-mesh strainer set in bowl. Transfer drippings to fat separator and let rest for 10 minutes. Reserve 3 tablespoons fat and defatted liquid (about 1 cup). Discard remaining fat.

Heat reserved fat in large saucepan over medium-high heat until shimmering. Add reserved neck and giblets and cook until well browned, 10 to 12 minutes. Transfer neck and giblets to large plate. Reduce heat to medium; add onion, carrot, parsley and bay leaves; and cook, stirring frequently, until vegetables are softened, 5 to 7 minutes. Add flour and cook, stirring constantly, until flour is well coated with fat, about 1 minute. Slowly whisk in reserved defatted liquid and cook until thickened, about 1 minute. Whisk in water and wine, return neck and giblets, and bring to simmer. Simmer for 10 minutes. Season with salt and pepper to taste. Discard neck. Strain mixture through fine-mesh strainer and transfer to serving bowl. Carve turkey and arrange on serving platter. Serve with gravy.