I'm not sure on length and weight. She's in quarantine so doesn't really get messed with at all other than cleaning, watering and feeding. I'll get stats on her sometime next year but generally I just go by the overall look of an animal. I'm offering several smaller sized prey each week because she dropped a clutch before coming to me and is still rebuilding. You should be fine feeding 1 prey item weekly but it really depends on the size of the snake and what you consider a small rat. I'd love to see pics of your pit if you have any.