I have never fed a % of their weight, matter of fact I never feed anything bigger than a medium rat to a BP (about 120 grams rat).
I just cannot imagine feeding a 350 to 525 grams rat to some of my girls and that's for various reason the main one being I want my animals to with consistency.
Feeding smaller preys once a week will allow just that, the animal eats with consistency and put on weight with consistency also.
Pre-breeding season I feed a little more heavily (females only), does not mean I give bigger prey I just offer every 5 days instead of 7 while they are taking it, it allows them to put on some weight before they start fasting.