so been tossing around ideas and this past week i took about 20mins, and made a better lower grille block.
Used from scrap pieces of coroplast lying around, a couple dabs of 2-part "marine" grade epoxy to hold some end slide stops.
1 slot Open at all times
other slots are for extra cooling when A/c is on.
At the moment they are Manual adjusted. Gonna go to pick-n-pull, for a gear shift cable to use for "on the fly adjustments" inside the cabin. I plan to Block the upper Grill completely.
Rattle can primer once it was secured with zipties. little over-spray on the chrome trim, but nothing a little diluted paint thinner cant fix