As long as you make certain the babies are thermoregulating n drinking on their own, I'd say bigger the cage the better for them. As babies they may be intimidated by a huge cage for a while but they'll adjust quick I'd bet.

Provide them with a humid hide in addition to a dry shelter of sorts. As babies they grow so fast, they shed constantly. They got pretty thick skin and in dry set ups it can build up easy or make the little guys so tight it iterfers with digestion....plus they love a butter dish with a hole in the lid full of damp peat.

Good Luck

Peace
Dennis