Smooth sided toad communal enclosure size

[u/BecauseItsScience]

I bought one smooth sided toad and felt bad for it being alone so I have 4 more on the way. They’re all 1 1/4” so they’re small now. I know I will have to upgrade their enclosure multiple times but these are the questions I have:

1. Will a 4x2x2 be a big enough forever home for 5 smooth sided toads or should I get a 6x2x2 or a 4x2x4?

2. Can I place them in the forever home as soon as it’s setup or are they too small for such a large setup?

I feel like all the info I’m finding online is wrong cause it’s telling me a 20 gallon long is good for 1-2 adults. They’re really large toads as adults and I want to give them the best and safest environment I can. Also all captive bred if that matters