Question for the Experienced Body and Paint Guys

Most people agree that it is better to spray the car completely assembled, but as you probably know there are issues with doing that, in not being able to paint certain areas, overspray into other parts etc.. My understanding is that if you, lets say, remove the front fenders, hood, valance, the trunk and place them in a way that they sit just as they sit on the car as you paint them, and you paint everything in the same day in the same garage/paint booth at the same time, everything should match and come out fine. so, the fenders cannot be sitting on top of a table, as the paint will settle differently on the sides of them, they need to be with the fender tops parallel to the floor and the sides hanging to the floor just as they sit on the car, and the hood has to be parallel to the floor just as it sits on the car. If the parts are painted on the same day in the same booth and the panels hang as they do on the car, there should be no issues. The biggest issue with painting the panels separate seems to be to do it on a different day, with different temperatures and atmospheric conditions. Plus when you mix your paint the mix may not be exactly the same, even when coming from the exact same can, especially with metallic paints. When doing this you just place your fenders next to your doors, and as you paint your quarters and doors, you then keep going onto your fender as if they were attached to the car, they will just be a couple of feet away from where they would normally be, and your hood will just be in front of the car, again just in front of where it would normally be. If done correctly there should be no issues.