Red Schneider wrote:
The question I would ask is: nose height aside, do you get to decide 'how much' air to send? I would tend to think that you have a given airflow and you're just trying to shape it.
Well, I think that the amount of airflow is roughly equall to the frontal projected area of the car less all the one that you don't manage to retain clean and within boundaries. ie: all the one that you send outwards of front tires.
Answering your question, yes, I think that you have to think how much air you are gona need at the top and bottom of diffuser and RW to achieve a certain DF. Then you'll find a way to shape it in a way it stays usable. You need goals or otherwise how can you improve?