Hmm, I would say anything over 200/250 is fine. You can't really say "a such and such aged bp should weigh such and such." There are so many things that factor in. They don't always gain weight like you wish they would even if you are feeding them good sized meals. I picked up three girls that are probably just a tad younger and all of them are within 10-20 grams of being 300. Then I have my het pied trio. I'm thinking they are about 4 months old and they are all right at or just barely over 200 grams. Something else to keep in mind is how much they weighed when they were born. I also have an '09 that's only ~400 grams, but he's a headache. He looks fine, but he is very small for his age. He's a tough feeder so there isn't a whole lot I can do. This is an '10 and him an '09, on the right
Just as long as you are feeding appropriate sized food every week, you should notice a little bump where the food is inside the snake, and your snake is gaining weight, you should be good. If they aren't gaining weight they could have parasites.
By the way I love your paint!!![]()