In my case I have the TC right next to the Verizon FiOs modem/router. So, I turned off the Verizon wireless so as not to create interference. As for the configuration, I set the TC to bridged not because I'm savy with these things but because the AirPort Utility on my iPhone told me to.
@LaPastenague, I'm confused about your suggestion the guest wireless doesn't work in bridge mode, mine does.
If you are able to run an ethernet cable from your Verizon FiOs modem/router to another part of your house, that will allow you to set up your TC a distance away to give you better wifi coverage in your house. Stone walls prevent me from doing this. If I need better coverage, I will buy the $99 AirPort Express and set it up in bridge mode working wirelessly from the TC.
I hope this helps.
Richard Ellis