"I generally just run a continuous GEC from the panel, to one rod, then to the next rod.Leave the wire on the surface, and bury it in a shallow trench after inspection...."
- NJwirenut

Me too. You would have to buy the proper megohmmeter for testing the rods in order to show the inspector that one rod is sufficient...it's much cheaper to just put the second rod in and not even have to be there for the inspection nor buy the test instrument.
Andy