Place 6 squash halves into a shallow baking dish. Pierce with a fork and brush with the 2 tablespoons of melted butter. Add ½ inch water to the pan and bake at 350 degrees F for ½ hour. Meanwhile, melt the 6 tablespoons of butter and saute the onion and celery. Mix in rest of seasonings and pour this over bread mixture, mixing well. Stuff each partially cooked squash half, then bake another 15 minutes, or until done.