I'm gonna throw out some thoughts
*The forward stagnation point is not a drag producer.Long before the air makes it to the body,it's already displacing to streamline itself,as demonstrated by Ludwig Prandtl almost a century ago.
Here you can see it happening to the 1937 Schl'o'r pillbug car.
*The side area of the bike is so large in comparison to the pressure bleeding ducts,that there might not be enough porosity in the body to mitigate the effects of a strong crosswind or gusts.
*Since you're relying on a vertical airfoil so to speak,they suffer tremendous drag when truncated like a Kamm back.It's better to have the trailing edges come together as a point,even if the curve is 'fast.'
