chris you need to use grease the pans then line with parchment paper and grease and flour again that is the proper way to do it .This information comes from rose Levy Bernbaum The Cake Bible and not my own so it is wise to do that way she is the cake expert lady and even for wedding cakes layers she uses that method wax paper is meant to be used because it can burn in the oven.there is a special type designed especially for baking it is oven proof wax paper isnt .I advise you not to skip any of the above steps in preparing your pans as you are making such an important cake the wedding cake as for using the cake mix part I cannot advise you but each box only make 2 9x2 inch layers and wedding cakes have several tiers of vary sizes so i canot tell you how much you need but it will be more then one or even two
Csally