Being able to put herbs in individually at different measurements

Hello, it would be wonderful to have a feature where we can input herb measurements for individual clients. For instances ‘John’ gets 50ml ginger, 40ml lemon balm, 15ml turmeric. Stacey has 60ml cats claw, 30ml licorice, 10ml ginseng.
Just for stock take purposes, this would make life so much easier. Some herbs cost a lot more than others, making an average ‘product’ cost really difficult.