Questions are always appropriate.
The wire forming the screen is a miniature telephone pole (exterior surfaces are not actually smooth-n-shiny), and causes aero drag much worse than you would suspect. The openings must be microscopic to keep anything dangerous out, and they're the worst on flow. A screen opening large enough to reduce drag only stops birds.
The screen area has to be like 2-3 times the air horn area NOT to reduce air speed and CFM.
The usual curved dome is wayyy too small. If the rules actually required it (and forbade a filter) my guess would be to use the 14" common base and land a screen 1/2-dome 14" OD, 7" tall on it - that's 308 in.2 or 15 times the air horn area.
Other 1/2-domes ranked by surface area:
5.125" wide (stock AH): 41 In.2
8" wide: 101 In.2
10" wide: 157 In.2