Breeding is not about space, in the contrary, it's about the animals being close to one another, very close.
Breeders will typically breed their animals in 32 and 41 quarts tubs and again they do not move their females especially during breeding season.
I breed females under 2000 grams in 32 quarts and females over 2000 grams and up to 4000 grams in 41 quarts and have done so for over a decade, so trust me you have more than enough space in a 55 quarts tub.