I think your on track with what your doing. I have a 750 gram Spider that has a bad head wobble. He is my pickiest eater that I have and I've found that giving him smaller rats helps him actually eat. I wouldn't say they are "weaning" rats but more like recently weaned rats, maybe a two or three weeks after it's been fully weaned. (sorry i don't weigh my feeders, otherwise I'd give you an exact weight.) As long as your snake is eating what you offer you're not over feeding in my opinion. Hope this helps!