How much to feed my BP?

[Megz]

If you over feed they can regurgitate, and then you can't feed for two weeks. Play it safe for such a small snake and only feed one correct sized prey item per week.

i understand always to measure on girth but over the years is there a specific number of grams you should meet in order to be enough for them. Would it still be 10-15%? Also how do you know if you over feed?