Streamlining of the line slide, or slider, is important as Mares had the University of Genoa (relying on my memory here as I have not rechecked it) conducted hydrodynamic testing to arrive at the shape of the slider used with the original "Cyrano". An effective hydrodynamic shape cannot solely be determined by the appearance, although a reduced cross-section presented to the flight direction is important, it is not everything. That "Cyrano" slider had the line angled and blended into the body shape in the manner in which it was tied, the problem with it was that it was not strong enough if used with other types of line and it also had to be tied properly to achieve the correct flow dynamics at the velocities it was designed for. Hence the trailing shape of the slider is important and I think this is being shown with Tomislav's rear cone as long as vortex inducing stepped transitions are eliminated from the rear shape to create the best flow lines. Think of the shape of a Tuna, that fat "teardrop" shape in side profile which has produced fast swimming, low drag capabilities over millions of years of evolution.