The boards do not drive the footage. (they help with HDV and DVCProHD codecs). But they are capture/record and external monitoring cards. So the codec needs to be want FCP wants, which is QT. NOTE: QT and AVI are just the wrappers around a codec. Apple software wants things in a QT wrapper.
This really should be simpler than even what that article states. First if you have FCP or Express you have QT Pro so need to buy that. You also have Compressor with FCP (don’t know about Express) so all you need to do is to convert the clips to 1280×720 ProRes and you will be golden. You can probably just convert the footage to a QT MJepg, just keep it the same frame size.