Firstly Mike, I'm jealous as fook.!!!!

Depending how you're getting there, I'm sure you'll be adequately filled in on best viewing points on the way across on the ferry as most people you bump into will have been before.
Personally, if I was lukcy enough ever to go, I wouldn't buy a grandstand ticket as feel it would limit the opportunity to walk around, change view points etc.

Hope you enjoy, I'll have to wait for the potted highlights on tv.