Preheat oven to 425 degrees. Thoroughly wash and dry the potatoes. Bake until soft, 45 to 60 minutes. Cut a slice from the top of each potato and scoop out the potato, being careful not to break the skin. Mash the potato well and beat in the sour cream, cheese, salt and pepper. Add more sour cream to make the potatoes light and fluffy. Stir in green onions. Spoon the potato mixture into the shells, mounding it slightly; place potatoes on a baking sheet. Dust the tops with paprika and return to the oven until lightly browned.