the only thing holding you back is really smell...
In a smaller tub, with 5-8 adults and babies, you will stink in just a matter of days.
Most of my lab cages are 10x19, and the lowest I run is 1.5. Most are way more than that. Sometimes, you have to adjust for murderers and cannibals. As time goes by, the cage dynamics change too.
I harvest anywhere from 400 to sometime 700 or more per week in 60 lab cages. Some of them are so overcrowded with babies at times, that they are literally crawling floors...But, within a couple of weeks, most of the babies are pulled, and the cage will go back to a reasonable level.
Most important part is, finding a good ratio for that particular cage, and quality rodent blocks to stop cannibalism.