I'm still not getting my question answered though about whether.....
Sum,
it's hard to get here a answer, due to this, that the answer based a combination of a lot of different factors.
But I will try, to get you a idea.
The disturbed airflow behind a NASCAR or Formula 1 is about 50 yards.
Behind this cars - in this 50 yards - is a very turbulance air - more - it's a vaccum air - this is the reason why a car behind a other car can go faster - the airpressure which the front car get, exist not behind the front running car - in other words, behind the front running car is "less" air
To your question, if the wheels could stand in line or stepped.
At first, with a short wheelbase, the rear wheel is full in the disturbed air from the front wheel - but this air is different than a air behind a car, due to this that the wheel is turning forward, which create a totally different airflow. The air behind a turning wheel goes backwards
at first - this sound very strange, but you can see it in a windtunnel.
When you cover the wheels inside and outside with a disc, this airflow will be much cleaner.
If you run a longer wheelbase, the airflow is a little bit cleaner, before it "crashed" into the rear wheel, which helps if you run covered wheels.
Much more important is the distance between the wheels and the car body, how far you be away from the body. If the airflow around the car is not touching the wheels, the car can go faster. In other words - if the disturbed airflow from the wheels is not crashing into the body airflow, the airflow around the body is smoother.
As you see, it's a combination of a lot of factors.
It will be need too long to explain here everything, but I hope I gave you a idea what all is involed into the airflow.
Let us talk at the Salt Talk about this issue. There it's much easier to explain.