I want to be able to customize the keyboard shortcuts for switching blending modes while using the brush tool. I switch back and forth between Normal and Clear mode hundreds of times while drawing and using my non-drawing hand to press Shift+Opt+R and (especially) Shift+Opt+N are so awkward that it becomes frustrating. I'm aware I could use the eraser, but this method works best while using the custom brushes from the Tool Presets menu.