My question is about the percentage of fragrance oil that can be used. I sometimes purchase fragrance oil from Lonestar Candle Making and their bottles have the IRFA categories listed, including Category 9 which is for soap. The usage rate is stated as a percentage. My question is, a percentage of what? The total weight of the batch, which would include water/liquid, lye and oils, or the total weight of oils in the recipe? As an example, if a fragrance oil said Category 9 usage was 11%, and I was making a batch that will weigh 46 oz. (total weight of liquid, oil and lye and include 32 oz. of oils), would the amount of fragrance oil I could use be 11% of 46 oz, which would be 5.06 oz, or 11% of the 32 oz. of oils, which would equal 3.5 oz? In reality I would not use that much fragrance oil (either 5.06 oz or 3.5 oz for a 2 lb. batch), but based on the stated Category 9 usage percentage, COULD I use those amounts safely? I generally use 1 oz. of fragrance oil per pound of oils. I'm just trying to understand how to calculate the fragrance oil based on the IRFA percentage.