I don't like to do that. With some otc waxes such as megs or mothers, mixing the two waxes might not matter a lot. With premium waxes, I have found that you will reach your best potential by layering (yes I said layering!) continuously with the same wax. Using other waxes may produce a shine, but clarity and range is what you are really after in a good wax. Pairing different formulas I have found could compromise the overall clarity and range that you could achieve with the dilligent use of one fine wax brand.
Make sure that you do well in polish prepping and lubricating the paint, and then choose one wax and go to town.
You can, however, experiment with other waxes. Just remember that the best way to judge a wax is to compare it on clean surfaces, instead of layering it on top of other carnaubas. Use a good digital camera as well to help you see what each wax is doing.
Or...at least this is what I think...
PS: A pure carnauba will layer (build-up) almost perfectly. You should wait a minimum of a day or so before applying wax. Overwaxing at a single shot ( 5 coats at one time) I've found will not serve you as well as one good layer that has cured for at least a couple of days before applying more wax.