Layering carnauba is one of my favorite things to do. I don't know why, but I find putting on a layer carnauba every few weeks or so to be very therapeutic.
I have been doing this for the past few years now. From my experience, I can honestly say that I have never observed any negative effects.
My advice would be to use thin layers, and definitely allow the first layer to cure (24 hours) before you add another layer.