New owner, 2 babies. Cage Size?

[Ripsaw642]

*Crested geckos*So i already posted this on another site, but because my posts don't show up for 24hrs at least, decided to post it here instead. I now have some pics, but i can't figure out why i can't post them......Is it because I'm a noob here? Here goes:

They're from the same parents, different clutch 3 1/2 weeks apart. Im hoping for 2 females, if not i'll separate them. One is just finishing it's first shed, hasn't eaten yet that i can tell. They're currently housed in a rubbermaid shoe box
(15x9x5 with 2.5"dome lid, approx 17l), with paper towel substrate, one big fake plant stem, 2 small real plants, 2 yogurt cup hides, and 2 pieces of pipe insulation wedged in there, with one having bottle caps of food and water. My question is, is it too early in the next few weeks/months to house them in a converted 20 gallon? Or should i wait and put them in my beardie's exo terra terrarium when i build a new enclosure for him in 3 months? I could also use the 20 gallon for one of my corns, and covert a 10 gallon instead. They're kind of staring at one another right now. Thoughts? Thanks!