How can any wedding photographer get the shots with the 800?

So, you are complaining about the AF ability of a camera you do not own and apparently you do not need and comparing it to a camera you do own which is enough for you

Sounds to me like you really want one and are doing your best to convince yourself it's not worth it so you feel better about what you have

Mine focuses spot on, left sensor and all. If I view at 100% then I can sometimes see some areas where it hasn't been perfect, but if I zoom out to a viewing distance comparable with 12mp then it's perfect.

When I had 6mp in my D50, I thought that was all I would need, until I got my D200. Of course not everybody has the technique to get the most out of 36mp, but then there is always the option of reducing it to 12 or 18mp and again it comes out great.

However thank you for the detailled critique of something you have no experience of, very informative