My Chinese have always eaten Carefresh Hamster Complete diet. It has a wide variety of seeds and pellets and corn. After going back and forth on the issue, I leave the corn in, despite their tendency to diabetes, I have not had any trouble and I think it is good for the skin.
Mine have loved moving the food mix around their cage in their pouches. It is hard to see how much food they need when they store it all over the cage, so maybe you could get them a scoop of seed mix each day (and sweep up the old twice a week), and then have a block as emergency food to make sure Pippa has enough?
Frosty takes all her food except the big pellets out of her dish right away. When I see the big pellets start to disappear I know it's time to add more food. Even though I sweep away a bunch of old food, it is no longer clean and she has eaten her favorite parts out. But really, I think moving her food around is one of Frosty great joys in life