[aerohead]

I looked at all of them and nothing really leapt off the page.
None of Volkswagen's low drag concepts have used anything as shown.
Typically, they're choosing wheels/covers which are very close to the MOON Equipment, spun-aluminum, convex disc covers as raced at the Bonneville Salt Flats.
Do you do a majority of high-speed cruising?
Any 'opening' in the wheel will induce a 'windage/ ventilation drag' upon rotation.
Even if enclosed behind full wheel skirts.
You need a minimum for brake cooling even though the brake rotors are designed to absorb all the kinetic energy of panic stops without fade or warping.
The GM Ultralite concept, circa 1992, has an example of minimum porosity wheels of low drag.
What's your ultimate goal for the car?