regarding the Nikon system,would I be right in saying that when shooting in LV handheld, esp above ones head,it would pay to keep the shutter speed as high as possible to compensate a bit for the mirror returning from LV mode.
To minimise blur,esp with non-vr lens.

There would be a longer time from button press to final mirror close in LV mode than normal mode,with same shutter speed. If ya know what I mean.

Nig.