Welp, I am either too discouraged or lazy to monkey with the wind tunnel idea, as I have done nada with it.
Anyway, I did finally get around to improving my mirror delete cover plates. While my previous version looked pretty good when I first completed them, the use of hot glue as the bonding material just got messy with sunshine softening it up. So all of my precision in that effort ended in misalignment, warping, and a hot glue mess to clean off. This new version however is assembled 100% with ABS glue (home made with ABS dust and acetone), and it is a better fit so has less structural stresses on it. I think the 3M tape I used to attach them will also pan out better over the long run. At the very least, they should stay in one piece if they do fly off the car.