I am curious why would you install a 100 amp service and only use a 60 amp main ?
Our inspectors allow us to bond only at the service panel. As I understand it, once you bond the neutral any point after that should be a feeder. Once we bond the neutral we ground to the water pipe and drive two ground rods, and that pretty much cover our grounding.
If there is no city water then we bond to any metal interior water line from the well.
I guess thats why we ground and bond at the service panel, saves alot of confusion. One of our fellows grounded at the meter and was promptly gigged for it and had to regrond at the service panel, makes for a nice neat package.