Hi, I created a worksheet for WR : https://docs.google.com/file/d/0B4fCtziVVxmyeG8tSzlXLWtKaFU/edit?usp=sharing
You just have to enter the number of hours, the goal you want to reach (in millions) and scroll down the hours on the left. You ve got charts in the other pages (real damage, estimation...) You can upgrade it easily, im not very good with Excel ^^