I have used both the full dosage and half. I have gotten better results of course with the 6 a day, but do still get results with half doses as well.
I believe Dr. Stout stated that after a set amount of time you could decrease the dose to three a day and be fine, depending on your goals.
I am currently on three a day and cycle back on to the full dose about 4-6 weeks out from a powerlifting meet.
Hope that helps