Also, be sure to record some room tone during the shoot. You can use this to add in a bit of “dead air” between sentences when needed. It sounds much more natural than just cutting the audio to actual silence, which can seem jarring.
Blackmagic has updated their drivers to version 9.6.8 which fixed the problem is PCIe cards not being visible to FCPX. I still have the problem of the only option being 720×480 29.97. In FCP6 I have the whole array of options for output.