Interesting topic. The way I have cleaned boards is to fill anti-static plastic bag (close to board size) with isopropanol and drop it to water path.
I will try 70/30 ratio with ethanol due to reasons mentioned earlier.

Do you rinse PCB after path? Sometimes I see residuals that probably should be rinsed but I am not willing to use water after alcohol-based cleaning path.

 

I would rinse it with water. If for no other reason just because it looks better. As long as the components are not moisture sensitive. Then blow dry it thoroughly. Or you can bake it in the oven at 250˚F for 10 minutes. That would boil out any residual water remaining.