You need to blend the mixture and spend time masking the untargeted areas. This brings the question, does spraying really saves time, even after all the additional masking time?

Well, it does. Spraying is around 5-10 times faster than traditional brushes and rollers. For every additional hour you spend prepping, you’ll save around four hours of time that would have been needed for brush painting. So even with the extra preparation time, you’ll still be saving time by quite a margin.