I’m all for diversity and mixing things up. I don’t weigh my snakes or their prey. I just feed them a prey size I think/know they can handle and they usually fluctuate between 2-3 prey sizes. My boas can handle large rats regularly but they eat mostly mediums with an occasional large rat. I also feed them chicks and jumbo mice as snacks. Admittedly, I feed a little heavier than some so that should be considered too. 😎