Man, I'm glad somebody else said it. I get tired of being the one that says, "Do you have a plan for all those babies," and "How are you going to prevent fights?" and "Quarantine new animals," and "Females can fight too, just house them separately."
So, to the original poster, consider my post 1 to the first opinion you got, including the cage size - my understanding was that 20 gallons was theoretically enough for a pair (though that would be the bare minimum), and a 20 gallon long is 2.5x1x1 = 2.5 square feet of cage floor. 3x2x1 is 6 square feet, or 2.4x that space for 3x the geckos, so yeah, that's probably too small for 6 geckos.
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0.1 Albino Leopard Gecko - Tigger
0.1 Crested Gecko - Pooh-Bear