No, there really isn't an exact science to feeding. We do our best to mimic nature, but we can't ever duplicate it 100%. 10-15% of body weight is approximately the size prey a BP would hunt in the wild. But this is why offering 2 prey items to equal that percentage is appropriate - if a BP finds a little mouse in the wild, he's gonna take it. But then he's gonna keep hunting til he's full - probably 1 or 2 more mice will do it til the next week or so. Incidentally, I'm not necessarily recommending feeding multiple prey items - just pointing out how it can work out sometimes.
Anyhow, that may very well help your kids to add a few grams. You can feed that percentage every 5 days or so if they have good appetites and a little less often if you have picky eaters.
Side Note: Ella ate 2 jumbo mice last night. She's about 1100 grams and the mice were 50-55 grams each. The last time she ate was 2 weeks ago. She'd been on a hunger strike from Jan-March and I'd had to restart her on live as she was still refusing f/t. 2 weeks ago, she ate 3 small live mice which only weighed in at about 20 grams each. Before that, she's taken a few live mice through April coming off her strike. So all in all, they'll eat what's appropriate.![]()