There are a number of views on this, which will give you lots of opinions to contemplate and choose from.
I prefer the Keep It Simple method. White cake only with white BC icing. 1" squares with a blop of icing on top, served in lidded plastic cups with a fork. I don't view it as a time when a bride selects her flavor. It's a time when she samples a bit of your baking skills ("and if you like my plain 'ole white cake, wait until your appt and you can taste my other varieties!")