1lb of wax =16oz. You multiply 16 by 7% = 1.12oz of FO. I usually use a calculator and a very accurate electronic scale. For the 3% beeswax, Multiply 16 by 3% = .48oz of Beeswax. Also to make it easier, instead of using 16oz of wax (1lb), I just use 14oz of wax, therefore 7% of 14oz is an even .5oz of FO, and 3% of beeswax is 14 multiplyed by 3% = .42oz of beeswax. I would first add the 3% beeswax and 1tsp of additive into the scale and then add the additional amount of regular wax to give an entire total to 14oz, then melt and add your FO to that.