A quick photoshop tip for the artists out there that make their own brushes: When you name your custom brush, add the size of the brush and the Flow number like so: "Ken's killer pencil-8p-30flow".
Many of my PS brushes have custom flow settings, unfortunately PS doesn't save that setting when you make a brush. So- by noting the optimum size of the brush and the flow numbers when you name your brush, you will always know how to bring your brush back to it's original coolness. If your new custom brush is also not 100% opaque, then it's good to note that number in the name as well. :)