The cheaper paints are cheaper because the have less pigment in them therefore it will need more coats for proper coverage. We do race cars all the time at our shop where weight is a consideration and we just use our modern Base coat/Clearcoat systems and still achieve the necessary goals for weight loss. The key for light weight in body materials as far as fillers ,primers , and paints is that less is more. Meaning that 1-2 coats of primer only when necessary, 1-2 coats of paint or color, and the bare minimum for clear coat, with a color sanding and polishing afterwards. The most gains are when the old fashioned grinder is used to 'Thin' out the base material.
