In some cars the wheel is set at an angle to the driverís body i.e. the left hand edge is nearer than the right hand edge. Given that most drivers have arms of equal length this seems an absurd layout. It is difficult to spot, but the measuring system I use shows it up well.
Two plastic profiles with slots sit in the window openings. Then the long profile (on the left) sits across the car engaging in the slots, so it forms a perpendicular to the long axis of the car. The long right hand profile is then placed so that it is touching the steering wheel. Wheel angle, as in the Saab 93 above, is immediately obvious.
Wheel angle seen from the front
Wheel offset requires that the centre of the seat back to be determined first.† Using the same plastic profiles as before, a laser is set up, focusing on the centre of the seat back which has been marked with a pin.
†Note laser line and pin.
Now the laser is projected onto the steering wheel
In this case above (Nissan Micra) there is no offset, but in the Kia Cerato below there is an offset. Sorry, the laser can be hard to photograph, but if you look carefully you will see that thelaser beam is coming down at the right side of the Kia logo.