A body louvers
Just trying to help with the projct Rob, as I'm interested in a set myself.
The .040" aluminium, I would have taught would've been strong enough.
Did you try with a small 90* bend say 3/32" at the front (upper) edges, or fold (roll-over the edge) for added strength.
And "yes" on the bottom filler panel.
All the best.
Giles