[sheepdog 44]

Basjoos, would having the leading edge of the wheel skirt recessed into the wheel well work (or be better) while still having the trailing edge flush with the outside of the car? I think of it like the scales of a fish where the front opening of the wheel well kicks up a fraction of an inch over the skirt, which does the same for the edge of the car. Or is having both sides of the wheel skirt flush with the outside of the car important.

From what i gather across several topics here, doing the best to minimize air going into the wheel well is important. Like on the Probe V series of concepts they have very good deflectors in front of the wheel. I would say minimizing the opening of the wheel well from beneath, and maybe even minimzing the volume of the wheel well would help. One car has an air vent behind the wheel well to vent pressure build up.

For Metro MPG's problem i think cutting off the back couple inches of the skirt would vent pressure while still improving airflow significantly over stock. You can always go with a fixed front skirt that just minimizes surface area of the outer wheel well to the tire itself. If you watch a second gen prius on a rainy day they kick up very little mist cause the wheel well isn't that much larger than the tire. If you watch a car with a big gap they're spraying mist from wells everywhere.

Does lawn edging running the length of the car help with it? Like extending the side of the car nearly to the ground with lawn edging?