Rob, here is some info for you. Better late than never, huh?

You are right, the second part of the equation for the toe calculation is to compensate for the camber of the wheel. This is because the laser level is mounted over the wheel’s center but is pointing downwards just slightly so that the beam hits a tape measure on the ground. This slight angle off horizontal introduces a very small angle change in the laser pointing due to the wheel’s camber. For our typical negative cambers, pointing the laser downwards to hit the tape measure will push the beam outwards away from the car’s centerline, and the amount it pushes out depends only on the camber and the distance the beam travels. Now, those two are closely related since if the tape measure is really far away, the laser pointing direction downwards will be very small. So it’s possible the formula could be simplified. But I think it would not be related to the distance from the center line.

The most accurate distance measurement from laser level to the tape measure is, from my experience, from the end of the level where the laser is shining from, since I was able to use a T-square to make sure I drew a vertical line to the ground. That means that half the length of the laser level needs to be added to this measurement to get to the center of the wheel hub. This is the “8”, i.e. 8 inches, for the laser level model I used whose total length is 16″.

Sorry folks, I never quite got to writing up parts 3 and 6. Maybe next time I do the alignment myself I’ll take photos and write them up. I wouldn’t hold my breath though, it might another few years :-).