TallMike: Yeah, I get that, and I'm starting to develop the ability to spot the various "wings". What I'm looking for is how to find the "weak spots" without brute-forcing my way through every cell in the hopes of finding a short inference chain. What WOULD help would be at least one more color, so that I could use, say, blue for all the options available, then red and green for the coloring of a chain. While I'm at it, I should ask for the ability to select the color on mobile -- not having a shift or alt key is a serious impediment. I know our kind host isn't putting time into this site, perhaps he'd permit crowdsourcing of the effort?
spellacked: I believe you are going in the wrong direction. The greatest benefit from doing Sudoku comes from changes in your brain, not changes in the tools available to you. Have you tried pushing your brain in another direction by temporarily banning yourself from using reds and greens even on expert puzzles? I did, and was impressed with the results. Eventually I began to see that it is impossible to observe how your brain works but it is relatively easy to change some of the ways it works in order to make it more effective. The results are obvious when they happen. But it takes time and effort.
Done. 1 start over.
DING. Only one Medium trick. But several moderate loners. 26.