I will just stick to AF. I doubt my efforts at MF would better it. I cannot see how LV would help me for my type of portraiture. Perrone, and anyone else who uses this method a lot, I'd be most grateful if you could explain to me how you use it. I'm not saying it's not possible, just that I can't work out how to do it.
To be clear to everyone, my original question wasn't aimed at discrediting the D800AF but to find out how people managed MF accurately in any DSLR. I only posted it in the D800 spot because there didn't seem to be a section more suitable.
Interesting point about the viewer. I was under the impression that the D800 had to downgrade the LV image due to the high resolution so assumed a viewer wouldn't have helped, but would simply magnify the unclear image. I have taken Roderick's mention of the magnifying eyepiece on board mind you and have one arriving tomorrow.