I have a customer with a 4 story home, 12/12 pitch metal roof that is being installed as i speak. if i'm to ground it i should do it now. Manufacturer of roof & local codes do not require grounding. I am concerned that if i ground it as my customer wants (he also wants a lightning rod with one of those glass balls on it) i may be causing a path for lightning? Installing surge protection for this. Thoughts and recommendations?

See 250.106 and 250.116 and the FPN