Ball python size to tub size?

I'm using the 15 qt Sterilite tubs, 17" x 11", for both my 70g baby and 350g female. I feel like Blackout (the female) looks a little big in there, but my eye isn't used to looking at BP caging sizes. I already even bought the 32 qt tub in preparation hahh...

How large do you keep your ball pythons in a 15 qt Sterilite before bumping them up to the 32 qt?

The 70 gram.. I would have in a 6 qt tub until around 350 to 400 grams..... The 350 gram is fine in a 16 qt tub until around 700 gram range... Then a 32 qt is fine for a male fully grown.. female once they hit around 1800 gram range I move to the bigger size tub ... That's just me but I been wondering what other people do...

Remember, these guys love small tight spaces so don't sweat moving up in size right away. Normally they live in burrows and/ or termite mounds and feel more secure in smaller spaces. Give them a tight small hide as well.

Sweet, thanks guys. =) I even bought a 32 qt in preparation, but I suppose that won't be for a long while.