With plenty of cover, any size would do. A 300 gallon glass aquarium with vines, structure, ground hides, climbing limbs, etc wouldn't be "too big".

These aren't ball pythons.

I put together 2x18''x2 exo terra planted vivs for the last pair of hatchlings I picked up.

As long as they have room to stretch out, thermoregulate, and perch, you're good.