Another approach that works for some players is to use the C major scale on those two strings (6th and 5th) to map out the other notes as referential to them. If your aptitude for memorization is quite high, this would be quicker.
Let’s say that you’re mixing a project and it’s arrived to you with phase issues built-in. You have a natural snare recording, but when you turn up the accompanying trigger track, it sounds awful. Usually it’s the above comb-filtering and/or a disturbing lack of low end. You can start by flipping the phase button, and see if that gets you where you need to be. Alternatively, you can zoom in on the waveforms and see what’s up.