gex laying box

[Bartman]

What should a proper leopard gecko laying box consist of. And should i breed my geckos in the 15 gallon or should i use my 30 gallon? They wont be there their whole life so i was thinking to breed them in a 15 so that i dont have to bring my other tank all the way from the garage for like a week. One of the geckos as of now is living in a 15 and the male in a 10 so i though just to bring him over until they breed and then seperate them. Should i seperate them or am i supposed to leave them?

thanks!