This is a great illustration of both the value of purchasing pfSense support, and the benefits this will have for the community. One of many is it forces us to write documentation. Several customer inquiries have resulted in documentation, some of which is already public (the rest will come with time).
A customer was having trouble trying to get OpenVPN working on multiple WAN interfaces. This lead me on an endeavor that resulted in the following documentation on how to make this work.