Steve,
It looks like you have a lot more suface area above the mounting clamp than below it. Does that make the upper portion "flutter/vibrate". If so, equalizing the torque produced by the airflow would reduce that (i.e. like a kids "teeter/totter"). Technically, it would be balancing the integrals of rXf for both top and bottom (perpindicular distance from mount to elemental cross-sectional area). In practise, you would increase the length or breadth of the lower portion to equalize out the aerodynamic forces. Of course, if no problem, then no concern. (Perhaps some of the upper air flow is already blocked or diverted by the windshield itself to help balance it?)
Nice job though. It really looks good!
