I plan on using either Vermiculite or Perlite. Hatchrite is practically the same thing, but more expensive.
This is a great tutorial on how to set :http://ball-pythons.net/forums/showt...-up-an-egg-tub
And some Hatchling care: http://ball-pythons.net/forums/showt...Hatchling-Care
Personally, I like going by Brian Gundy's egg box Medium:Water ratio. It's equal weights of water and medium.