I'd bump her up to hoppers. If she can take 3 fuzzies, she can take a hopper. That may help. Again king snakes are garbage disposals. Once on that prey size I would stay at 7 days. That's me though. I've had no issues with it.

My milksnake is the exact same way. About 3-4 days after eating he is out and about and ready for more. I still feed him once a week and he's growing rapidly.