I think the Diallo method 3 is just fine for lots of people. The only thing I would caution people on is that some papers respond differently to the same ink limits, and that the cross over points in the raw curve might not match with what is being printed. In MOST cases this shouldn’t really be a problem if you don’t change the raw profile’s ink limits. However, even if you do change the ink limits (assuming they are all changed to the same value) QTR's built in overlap (when using only three gray inks) should smooth over any possible banding, and there shouldn’t be a problem linearizing. If you had more that 3 gray ink then it could prove to be more of a problem.
The reason I suggested trying to correction curve tool was because you said the linearization wasn’t working properly, or that the resulting profile was not linear. Using the gray curve settings to get it in line first can solve those problems and make the last linearization step a breeze. I never needed to use the gray curve setting until I was profiling ink sets with more overlapping inks with the occasional linearization error. This thing started as more of an experiment to see how the QTR linearize curve differed from a home made linearization function. It seemed to work well so I formatted it in a way that other people could use it too. It isn’t essential, but helpful in some situations.
So I think the Diallo workflow 3 is a good way to get up an running with minimal effort, but going the extra step with workflow 4 can make the final prints even better. I always advocate for trusting your own eyes, not relying on presets, and knowing what is possible with the materials. That way you can know that you are getting the most from the papers and inks, and edit then the files to match. With the proper tools, it isn’t that much additional work to get it right from the outset.
Richard Boutwell