easiest way to mix methanol. the washer jug method. 80/20 or 50/50 without weighing or measuring.

this method is something that I came up with a few years ago after the debate between weighing methanol by Mass or by volume. I bought a hydrometer and found the exact content needed for 80/20 and 50/50 using a washer container and 3 marks.
original test measurements were done at 68° f on a level surface.