I go with the 10-15% rule for babies and yearlings. Once they get over 1200g or so I just feed small/med rats (usually 70-100g). I too have found that they eat more consistently with smaller meals. For males I just stick with small rats (55-70g). This is not to say however that I always go by this. If a female has just laid and is back on feed I offer bigger meals (100-200g depending on the animal) for a while, till they loose that "skinny" look. Then they go back to a small/med rat.