ok what you said is fine. But ask yourself as to what happens with the center of pressure when a wings stalls with out v/G as to one that does have them. We spent many hours testing in the wind tunnel at Boeing. Which at that time involved the 737and 767. As the boundary layer is does not move over a wing it remains fairly stationary.so placement of the VG was critical. To prove this.Go wash your car then take it for a drive to dry it off. The water will remain. on the surface. The Vg generators are soley to increase the blounary layer thickness which will give added control at slow speed. Thus delay air flow seperation. Which in fact has an effect on the center of lift and the center of pressure. Period.