The first thing you have to understand is, you have a reptile. Its ability to consume and digest its food is controlled by the enviornment(extotherm). Both temps and humidity are key, as well as mental stability(security) are important.
To judge how much a young snake can eat is very easy. Just look at it. All snakes normally grow long and slender, not skinny or boney, long and slender. If your charge is growing long and slender, then feed it all it will consume. Once your snake reaches sexual maturity, it will bulk out. Then you have to judge your feeding by other means and your goals.
If your charge is thick or fat, not growing longer, but instead getting fat, it means the temps are warm enough to allow feeding, but not growth. Instead of investing the energy into growth, its storing it as fat. In this case, the higher temps are marginal, the temperature range needs adjusting, increase the high end of the range.
I have often fed everyday even several times a time. If the above conditions are met. In these cases the offspring grow very quickly and healthy. Again, its the enviornmental conditions that can cause a problem, not the frequency of feeding. I often say in personal conversations, they are not eating donuts, which means, they are or should be consuming balanced foods.
Many keepers form a paradigm of schedules, which really have nothing to do with the snakes, its about them. Their conditions they set, they make statements, while these statements are fine for their conditions, they are not all inclusive. In other words, if they would change their conditions, they could change their schedules and vary their results. The old saying applies, its a F--l that does the same thing over and over, expecting different results.
A goofy analogy, in nature, if a watersnake was born to a pond with tons of baby fish and frogs and tadpoles, this watersnake could grow very quickly and be healthy. If that watersnake was born to a pool that had almost none of the food items i mentioned above, it would indeed grow very slowly and still be healthy. The key here is, in nature, they have a useful range of temps to acomplish their tasks, they normally can get as hot as they want or as cool as they want. In captivity, they can normally do neither, or none of that. They can only do what we allow them to do. The advanced answer is, what are you allowing your charges to do?
Reptiles are the ultimate conservation device. If food is scarce, they lower their metabolism and conserve energy as long as possible. In other words, move in slow motion, if food is plentiful, they increase their metabolism and do life functions are a much greater speed. Their lifes are spend going back and forth between these as conditions support.
Remember, in captivity, its a constant adjustment, your task is to monitor the individual snakes(in this case) and adjust conditions or food consumption as necessary. Necessary is based on your snakes potential abilities and your goals.
And yes, a pyro in both captivity and nature can consume fuzzies within a few months of hatching, under supporting conditions. I use the word support because, its normal and natural for reptiles to grow slowly or very quickly, depending on the quality of the enviornment(support), thats how you judge the quality of the conditions. Consider, its rare for nature to have the same support year after year, in fact, its constatnly changing, yet in captivity, some have it down to 1 degree and never changing, how natural is that? Good Luck, FR