My appologies gengis, I see whare your coming from. What, if any, is the the effect on the 747 if you allow the aicraft to be out of trim by only a small degree. I have yet to try it on the 737 but I have noticed on the 146 that a required trim of 4 units set to 3 units will practically have no difference on the feel of the controls.
I'm mostly wondering after doing a few 747 loadsheets with freighters how noticible the trim would be if I was out by a few decimals of a degree.