Actually, from an efficiency standpoint it's probably the most efficient way of doing a bunch of small parts...that's why the factory and suppliers did it that way. Think about it: twisting and turning with the spray can to get paint into every nook and cranny of a bracket or panel versus simply dipping it into the paint and pulling it out, knowing that it has complete coverage. Even in terms of economy (another big consideration by GM), it makes sense. Bulk paint is cheaper than spray cans and without overspray the wastage is somewhat minimized. The trick is to get all of your parts ready and make a reasonable estimate of how much paint will be needed to cover them all. Running out of paint in the floating layer screws-up the process of course, so there will be some wastage there, but no more than overspray if you're careful.
