The useful distinction is the appearance of the white and the amount of the base visible through it. A pale RGB value cannot tell you whether a coating is translucent.
Check coverage
Compare photographs made with a similar base and application. A milky description is a starting point, but the product information should establish the intended finish.
Choose a role
Use a clear white contrast for a defined detail, or a softer white impression for a quieter palette. Test the selected product before relying on a particular number of layers.