How much to feed Lucy depends on several factors. First, how much does she weigh. Then, since she is still unregulated, her body can not process the food correctly. Diabetic cats can need up to 50% more than non-diabetic cats.
Is Lucy telling you she is still really hungry all the time? Is she losing weight?
My 3 cats all need different amounts of food. ECID. Wink is 10.4 pounds, needs 7-8 ounces a day but he is my diet controlled diabetic so he is not starving all the time. Monet get 6-7 ounces a day, he is my big boy 12.2 pounds. My little civie Delta, 7.2 pounds only gets 4 ounces a day to maintain her weight.
When Wink first came to live with me, he could eat 2 5.5 ounce cans a day, easy. He has slacked off some since then.