Here's how you theoretically should set up the steering for a passenger car. 
This will make the car turn right under normal turning conditions.
Front or rear steer would provide the same steering geometry.

As is obvious, front steer can be tricky, because the tie rod ends need 
to be outboard of the balljoints, making it hard to fit if you don't run huge 
rims or have very short steering arms on the knuckles.
This setup will provide "positive Acherman" or in effect 
toe out on turn, 
which is desirable on daily driven passenger cars.
As you can see, a longer or shorter wheel base will alter the desired angles 
of the steering arms.
My Chevrolet Caprice has almost no toe out on turn, so it's "neutral ackerman", 
I guess. This is a compromise due to the fact that the wheels and brakes are 
in the way of making positive Ackerman.
Negative Ackerman, or 
toe in on turn is used in Formula 1 cars and other 
extreme cases where very hard cornering is happening, this is a whole 'nother 
can of worms, not applicable to cars driven on public roads.
As long as you drive straight on a road, the Ackerman angle doesn't really affect
 how the car drives. Given that, it's not a thing you have to give much thought unless 
you're designing your own steering arms or knuckles (uprights).