Randy, thank you for investing the time, money and effort to conduct these comparisons and then posting them for all of our benefit. Seeing your updates is like watching the next episode of my favorite series ...
If you don’t get the results you’re looking for in the passive shields, one thing you may want to consider if you think it’d be worth the effort is a little more separation between the shields to avoid one influencing the other and to promote airflow. When I did the side by side with the Davis FARS and the 7714, I initially had it set up as you do. I ended up getting better results with more separation (whether it was fan exhaust or airflow/solar shading I don’t know.) Not to say you’d get the same results, but just throwing it out there.