Create a Brush Shape or "Mask", independent of the Brush Preset

I love Photoshop, I love to paint in Photoshop and to make custom brushes, but the workflow could do with improvement.

When I make a completely new Brush Preset, I usually want to 1. create a black-and-white stamp on the canvas and turn it into a new Brush Shape. Then I want to 2. choose some Brush Settings to decide how my new Brush Shape behaves, and test and refine my new custom brush. Then, finally when I'm satisfied, I want to 3. Create a Brush Preset.

Please see the attached image for a more illustrated guide of the problems and possible solutions. Thanks!