Alignment,

[camoit]

I think there might have been a part missed from the original post. The hole thing was put in the Wiki with step by step instructions. The reason you put it on a turntable and rotate the wheels 20 degree is to locate the vertical line through the spindle when using a caster / camber gage. I never tried the level technical. I have the tables and gage. When turned out 20 deg the spindle is set at 0 for the caster. Then as you turn back to straight the gage will rotate. Even with the brake applied. Unless you are using a laser system. It's self leveling but you still need to rotate 20 deg.
The deg does change as you are making turns. From 0 to + and back to 0 again from lock to lock. If that makes any sense at all. Just use 2 fingers on one hand and the other as the spindle and move the hand that is the spindle. The more the caster the larger the change is through the range of motion. This is why you add more + caster to the right side of the car then the left. This will push it up the road crown.