On a service of that size what other made electrode will be acceptable? I am not sure I would be comfortable with 8' rods, no matter how many they drive. If those are hooks tied to the footer steel, I might be OK with several of them bonded to a #4. I think if you get 6 or 8 of them bonded and then pour that second load of concrete I would put that up against anything but a ground ring.
BTW I have heard of them requiring chipping down to footer steel here when the #4 was lost/stolen. That is one reason why most AHJs were OK with the turned up rebar solution with a 20' stick snap tied to the footer steel for 15 feet or so and about 4' of it turned up in the wall but that was usually 1&2 family.
