Sorry to bring this up, but I still struggle to understand why someone would think that the stiff side is always the same spine as the next arrow with a stiff side. The spine is important. You may have one arrow with a stiff side that the spine is equal to another arrow with the weak side of the other arrow. Thus, it is better to tune by moving your nocks per arrow. You should still float the shafts and mark the heavy side for at least a starting point, then shoot the arrows for grouping and continue to move the nock around until the arrows group good. Each arrow is independent of the other, thus should be treated separately.
One final comment. If you have a heavy side it means that there is an overlap of material thus creating a stiffer section. How much is dependent on the overlap.