Here ya go, hero, your own words. Wrong, just plain wrong. Look at the chart from your own component.
The voltage drop across that diode increases as current goes up. They all do. For an increase in voltage drop, you need an increase in resistance.
The diodes are your choice. They are not any better than a proper shunt. What you want to do with your own car is your business. I did not put a single word in your mouth. You invited questions in the first post, and I asked one.