I agree that it makes sense to set the alignment under the conditions that the car will be driven under and that adding weight is advised by the Alfa manual. But then again, is adding driver weight in the same realm as changing caster and camber on one side to compensate for road crown? Adding driver weight for alignment seems to be as controversial as oil viscosity when you visit other car forums, that's why I am curious as to which parameters change with the addition of weight and in what way they change. Under occasional spirited street driving will I even notice the change? I was on a hot rod forum that the poster swears that all of the race car shops that he has been to set ride height and corner balance with the driver in the car but set caster, camber, and toe with the driver out of the car. How much of a difference will it make with my 125# wife in the passenger seat? I copied the following question from a post I added to in the suspension forum:
Home shop caster setting
Will this work to get a fairly accurate caster setting: Use a laser level to assure that the floor is level where all 4 tires contact the floor (shim under the tires as necessary), set the front wheels going straight forward, place a 24" carpenter's level plumb(vertical) in a machinist's vice placed on the floor forward of the ball joints, measure the horizontal difference in the space between the threaded stems or (turning center countersinks) of the upper and lower ball joints and the level, measure the vertical distance between the threaded ends of the ball joints, then do the math to determine the angle? caster angle= tan- (horizontal measurement difference distance divided by the vertical measurement between the ball joints)