Rinse lemon and orange and thinly slice them, discarding seeds; quarter the orange slices. Put fruit in a 4- to 5-quart pan. Add honey, sugar (use the smaller amount if you prefer drinks on the tart side, the larger if you want a sweeter flavor), cloves and allspice. With a knife, cut the cinnamon sticks lengthwise into thinner strips. Add cinnamon and 2 cups water to pan; bring to a boil over high heat, then reduce heat and boil gently for 5 minutes. Pour Prosecco into hot citrus base and heat until steaming, about 8 minutes. Keep warm over low heat. Ladle into heatproof cups or wineglasses.