Tub sizes?

[MitsuMike]

Is it true that a ball python under 400g should be kept in about a 15qt tub? The breeder i am buying my mojave said that I should wait till atleast 400g to move him up to the 35qt. If this is true, then I need to down grade my current snakes because they are in the 35qt and not even 300grams. Any thoughts would be appreciated.

My pastel is around 120 grams and still chilling in a 6 qt. My logic is this. I buy a hide for that tub. Example: 6 qts have the RBI small hides, 16 qt have flower pot bottoms. Now once the snake grows out of the hide it's in I upgrade tubs. My normal and spider just got upgraded to 16 qts not to long ago so I would prob say they will be in there until around 500-600 grams. Then I gotta make a new rack for the 41 qts that they will stay i for the rest of their lives. I mean I think the difference b/w the 35 and 41 is not the big so might as well upgrade the whole way so I don't have to build ANOTHER rack. haha