Panorama and Prod firewalls

Hi, we are in the process of deploying panorama. However our Palos are already in production. So extra care must be taken. Any good recommendations on the best approach on how to import the locally managed prod firewalls into panorama, while avoiding outages?

Was also curious, if you can initially add the firewalls to Panorama for logging purposes and switch to central management at a later time/date