I ended up using a bonding bushing with a #4 bare bonding jumper from the neutral/ground buss... my intentions were to insure ampacity in case of a fault.
I now use PVC insead of GRC Nipples to remove the extra costs and concerns with this particular setup. (From advice given by the guys here! Mainly Bill...)
To this day the inspector readily passes services with GRC Nipples, Concentric KO's, and no bonding bushing or locknut. I even left a message on his answering machine concerning a question with 250-94, but no answer.
