I would think a black heavy gauge screen would be better than a bunch of random holes in the plastic.
Actually a heavy gauge black screen mesh in to replace the plastic with the added holes. Then set behind that, a second identical screen back a quarter inch. (or even a pattern drilled in a solid block, or vanes tilting UP diagonally to kill direct water intake
This would smooth out the air coming in and it would be an even, higher pressure zone at speed inside the cavity. The random small holes one cannot tell what effect they have at speed. With the air near a hole being pushed one way, and the air at the hole being buffeted by the adjacent no hole area bounced off airflow.. (a mess aero wise)