So I contacted my vet this afternoon to confirm numbers. When I got him he was 300 grams and dehydrated. by the time I got him to the vet 3-4 weeks later he was up to 440 grams but was no longer dehydrated. About 6 weeks later he was up to 495 grams meaning he gained about 55 grams in 6 weeks. He did just take a dump which brought him down to 475 but since the vet also weighed him pre-poo I think the 55 grams is a better comparison. I have attached a picture of him when I got him as well as a few taken yesterday to show body condition since it looks like he might be overweight based on the chart you attached but he does not feel squishy like I would expect fat on a snake to feel. he does have some small bumps around his vent but also does not have the fat rolls when he curls up unless he folds over on top of himself.

This is Waffles shortly after I got him home


The following were taken yesterday hopefully demonstrating body condition.