Feeding a Parvo Survivor?

A few weeks ago, we adopted a 2mo old Pit Mastiff puppy from a shelter. A couple of days after we got her, she was diagnosed with parvo. After vet treatment, she's completely recovered and is almost as good as new. The problem we're having is feeding her. She is obviously ravenous and can eat a lot of food super fast if we let her, but she's quick to vomit if we feed her too much or if we let her eat too fast.

The only food she'll touch is her large breed puppy kibble - she hates people food, the healthy, puppy-approved people food like chicken and rice, and wet dog food. So we've been measuring out her food and through trial and error have discovered she can keep down 1/4 cup of kibble three times a day (a fourth feeding and she throws it up, at 1/2 cup at each feeding she throws it up). We've been able to try 1/3 cup today, so far it's been successful.

But, by restricting her food, and with her being a giant breed mix, I fear we're starving her. She's been home a week and hasn't really gained any weight. How much should be feeding her? Are there any tips to help her get what she needs without eating too much and too fast for her recovering GI system?