I'm also Red-green colourblind, and also use a mobile app to check RGB values of things! I also use a Windows traybar app that I wrote with Delphi about 15 years ago, which gives me a dropper I can use anywhere in the screen to see RGB values.

I've also noticed that it's much more difficult to differentiate tones and colours of small objects.

Cues were mentioned in the article, and I think I subconsciously rely on these a lot. For example, with traffic lights I know what the colours should be from top to bottom, and so I "see" them as the right colours - yet if you took photos showing only the colours in the abstract, I couldn't tell any difference between red and amber, and indeed I wouldn't be able to accurately tell you what colour any of them was.

Something people find interesting is that I often don't know what colour something is, but I'm often able to narrow it down to 2 or 3 choices - usually based on context and other cues, and also based on how I know I can misperceive colours. For example, I know I often see pink as grey, so if you showed me something pink, I might think it was "pink, or grey or green".

Another random anecdote that demonstrates the use of cues: years ago we had an old CRT TV, and every now and then it would suddenly display only in black and white. It really annoyed my wife, but I never even noticed - I guess in my head I "saw" someone's coat as red, for example. My mind just kind of filled in the blanks, like I suppose it must always do.