There is no rule. It depends on the animal, what you are feeding, how often you are feeding, and what you want from the animal.
You are raising a pet so you want him to be happy and healthy and live a long life.
In that case, less is more when it comes to food.
A lot of caring for reptiles is an art, not a science, please keep that in mind. Yes, temps and humidity should be correct, but some people say 87F hot side and some say 89F. Is one right or wrong? NO. As long as the animal is doing well. Some people feed smaller meals more often and others larger meals less often, etc.
If I were you, I'd be feeding appropriate sized meals every 7 days for now. I also would only weigh your BP when he's empty - having done number 2. Also, same to scale to same scale. If the breeder said 100G I wouldn't take that verbatim on your scale.