Is this an existing LP system?? Do you have any previous test certs for the system?? If it is and older/existing system, and the individual electrode values have been previously recorded, then all you really need, is the overall Ra value. Which to comply will need to be under 10 ohms, unless otherwise asked for individual electrode tests.
Electrode testing isn't the only tests you need to perform on a LP system, all joints in the air conductors system will also need to be tested with a high current Ductor tester... Don't forget to test the Test Point(s) on the down conductors after electrode testing and reconnecting them... lol!!