Fiberglass hood mods... crazy?

it doesnt...
the top edge of your windshild/roof area to a small degree my have a plow efffect..but its mostly the grille and your front edge of the hood..
the high pressure air in the cowl is air that is circulating (like laying a large roll of paper towel accross your hood/cowl..despensing paper towels into the cowl ..and or cowl hood opening...
the front fascia..(grille)will dictate more of how the air acts... if you block off the grille and allow the air to run up over the hood you'll have less under hood air..and more available air in the cowl..
the air going over the roof has the co-anda effect...there is a boundry layer there...this creates a suction...if you where looking to remove air from under the hood..you would need it to exit where there is an extreme low pressure.
like the top of the roof with a Naca duct...
or theoretically where the fake ducts are on a charger door..fwiw.

Mel.