Usually the fronts are not as concave as the rear because they are typically not as wide. There are two ways to achieve that concave look, run a wider wheel or a lower offset.

Usually the front doesn't allow for as wide of a rim as the rear does. And if you were to run a crazy low offset to get the concavity, the wheel would stick out from the fender and would most likely rub.

It all depends on the car and what kind of offset and width the car allows.

Thanks for the explanation. For the above, what would be a good square setup specs for an x sedan?

Those look great