How much is too much food?

I've seen a number of threads here and discussions elsewhere discussing ball python feeding. A good chunk of them seem to focus on just getting them to eat regularly. My question is, if you have a ball that eats anything you put in front of her, how do you regulate it? With my corns, the closest together they ever get fed is 5 days and if they aren't pooping in between, it gets lengthened out to 7 days. With my ball, I don't think it would make sense to wait until she poops to feed her again. She's pooped once with me (fed 3 times) and it was smaller than I expected from her. Is that because she's not getting enough or am I just worrying over nothing?
Her current schedule is every 5 days, she's getting a large rat pup. They are slightly smaller around than she is at her largest and I think she could handle larger prey (once again, thinking from a corn snake point of view here). Tonight, I gave her 2. 1 was a very small pup (size of a small adult mouse) and then a larger one. She downed both and then kept cruising her cage, reacting to any movement outside with interest. Weightwise, she's gone from 225g to 271g (empty this morning).
I'm careful with my corns to keep them from getting overweight as it can cause issues with egg binding and I believe there are other health issues it can cause as well that just aren't proven yet (heart, etc.). With Ceti, I'm not sure what is overweight for her size to use that as a guide.
Any input would be much appreciated as I would like her to grow well, but I'd rather wait an extra year to breed her to know that she's in good condition and not just 'bulked' up to the right weight.

There are some BP's that will only poop after a shed so there is no reason to wait to feed until then.

For young BP's I feed them every 4 days. Once they get up to 500-600 grams I move them onto an 8 day feeding schedule. 4-5 days is the minimum amount of time between feedings, as it takes a day or so for them to digest.

For young BP's I feed them based on weight. 10%-15% of the snakes body weight in rodent.

So a 100 gram Bp would get a 15 gram rodent. (100 x 0.15 = 15)

For older BP's you want to feed a rodent that is about the same width as the widest point on the snake. (this also works for young BP's)

Alright. I'll keep her on once every 5 days and start weighing the pups to see how heavy they're running. I got a mixed bag so that I could change size slightly as needed so that should be easy enough.
Thanks for the help. :)

I'm guessing she needs slightly bigger prey. The rest of this ^^^ is what to follow.