How much Prep for Stone Tile
 

I'm installing 250 square feet of 16 inch travertine tiles in the kitchen with flextherm heating wires beneath.

I've taken out the old tile, removed the old plywood and have placed new 3/8 inch plywood ontop of the 5/8inch subfloor.

I wonder if this is enough? should I use something like EASYMAT to further protect the tile, and perhaps even insulate the floor so the heat goes to the floor rather then heating my basement roof.?

I really need help.

My Question is ...

Is this enough prep for the tile, or should I consider a very expensive addition of EasyMat with Soundgard Technology as well?

Thanks for your time.