My painter said he'd mix a flattening agent to the paint with a clearcoat but at the last minute asked me how much flat should he add. His first attempt was very cloudy/hazy especially along the sides. He is going to redo it. But, Besides the haze the flat wasn't flat enough. How much flattening agent does he need to add to get it to look like primer. 1 to 1 ratio? 50%? Please help me.