I made one using grams, and the dry measurements seemed off to me... so the second batch I made using volume and tested the weights with my scale. (farmgirlfare.com)
They will rent a scale for a full 24 hours and do multiple test weights; at least twice in the morning, maybe twice in the afternoon, twice at night. (pregnancymagazine.com)
Once the milk is in, you can do pre and post feed test weight. (pregnancymagazine.com)