Hello Greg,
I am having good success using the exposure bar at the time of shooting rather than the histograms, and I tend to check images using the histogram or the zone system after. Using this combination seems to output reliable results, matching what I am seeing when I open my RAW in the computer. As a general rule, I always try and keep my histogram as much to the right as I can, to record as much information as possible - but I always prefer to do so without burning any of the channel, though. So, depending on the scene and light conditions, I might go a third of a stop or two under what the camera considers as perfect, or the middle of the exposure bar, just for safety. Of course, since there are so many different shooting situation the above workflow may vary: i.e., when shooting into the sun I am not worried about burning highlights in and around the sun; when specular highlights are present (i.e., reflections of sun on water) I don't worry about these as well; and so on.
Hope this helps, best regards
Vieri