It is even more simple and efficient to do it in camera. You not only get a lot more images on a SD or CF card, but any post processing is much easier too.
Today we shot an Event using the D600 with Large Fine JPEGs and Quality Priority. The D800 Medium size Images were nearly the same size and Quality, Plus I had the advantages of more controls and comfortable grip.
I will continue to shoot the largest and best quality images when I need them, but I have found the solution for my Event Photography.