The top wax should be exactly that, the top. Mixing media with other waxes (especially different formulas or inferior waxes) will run the risk of you hampering the ultra sharp resolution that only a fine carnauba is capable of achieving. You can still get a shine, but the clarity and depth potential is what you really want from a carnauba, which could be jeapordized by mixing different wax formulas. You should only top a carnauba with something relatively neutral in composition, such as a QD.
You should think of topping, if that is what you want, by compounding your efforts with more layers (yes, layers!!!!) at different intervals...give yourself at least a week in between deposits, of the same wax.
I've followed this methodology, and at the risk of not sounding humble, I have not been disappointed in my waxed finishes.