I built a fluid bed that utilizes 3" diameter and 3" tall cups, and want to purchase some powder paint. Jig heads will be the only items painted. How much powder would be used in this size cup? I was told 2 oz. from one person and 4-6 oz. from another. Multiple colors will be ordered, so wanted to keep the costs down. It seems a lot of people use Pro-Tec. What are the opinions about Columbia Coatings, Powder by the Pound, and Caswell? Thanks.