The Flutes on this baluster span a total distance of 21″ (this dimension is constant, and is not affected by the length of baluster you purchase. Flutes will always be centered.
StairSuppliesTM offers balusters in two styles, Contemporary and Traditional. What varies between these two styles is the turning and block length, see below for details (click on images to the left to see examples):
The turning on these remains the same no matter the length of the. The additional length of the balusters will be added to the bottom block. This makes the turnings match the slope of your handrail.
The bottom block on these balusters remains the same, no matter the length. What varies is the turning length. This makes for a more staggered look, as the turning begins at the same point on all balusters on each step.