I plan on keeping babies in the 2.7qt tubs and Juvies in the 6.2qt tubs until they hit about 350 to 400g because they have a larger floor in square inches than 6qt shoebox just not as tall.

The 6.2Qt modular boxes have a interior of 192.5 square inches whereas a sterilite 6Qt shoebox is only 97.5 square inches

After that they'll be moving up to the sub adult/
male bins which are 25qt and my breeder females are housed in 41qt sterilite bins.