After using my Pyrex measuring cups for decades, I finally got tired of the cleanup and adding up the units.
Now I get mixing cups from my paint supplier. Plastic, around a quart, that have a series of proportion scales printed around the outside. 4:2:1 or 3:2:1 or 4:2:1:1 and so on.
You pick the scale that matches the paint you are using and with in the vertical column for that scale are 3 or 4 columns of numbers.
If you are mixing 4:2:1 for example, you pour in paint until the first column reads say 8. Then you add thinner until the second column reads 8, then add hardner until the third column reads 8.
Perfect 4:2:1 mixture, no math, no cleanup.
Sometimes we do get smarter when we get older.
