Back in the mid sixties my friends father who was a pilot had a Buick with the holes in the fenders, the car would sit for month while he was away, I thought they were neat till I saw close up they where Fake and closed off...
Back to that Under panel idea, I knew I saw this before ...
https://www.rallysportdirect.com/par...num-underpanel
So 15 minutes of your time saves you 300$ not bad!