The Sumiko Master Set is a very good system for speaker placement if you follow the directions. Certainly makes the speakers behave much better. I've used it for many years myself to get the speakers in the ballpark and then fine tune a little at a time.
While any test CD with low frequencies can be used to fine tune the speaker positioning, I think actual music is a bit easier as it spans a wider bandwidth of frequencies and not just some narrow segment. Speakers themselves vary in their frequency response across the whole audible bandwidth so tuning for a good overall "blend" of bass present in music to the room makes more sense. You can easily hear how the bass notes couple to the room and what effect that has on the frequencies above that encompass the all important midrange.
In fact I threw this little video together using the song they suggest in the article. For this example I moved the speakers out of my position since they are not difficult to move and my whole system is still burning in, so I don't mind doing it.
Starting from scratch, I lined the speakers up against the wall playing the Jennifer Warnes Ballad of a Runaway Horse and paying attention to the bass notes with the left speaker, I quickly found a place where the left ANCHOR speaker started to give me well articulated bass notes. The bass instrument should sound as each individual pluck is well defined and does not sound lumpy and bloated. Then as the article describes, I fine tuned the position of the Right speaker. Now, in my room it just so happens that they are both happy with being approximately the same distance from the front wall. It will not always work out that way. You can fine tune the listening position then to compensate and set up a more precise listening triangle with further toe-in and equal distance from the listening spot to the measured edges of the speakers.
Unfortunately YouTube compression and the iPhone mic can't reproduce the bass very well but you can still hear in the video that the bass response is well integrated in the room and that the lower midrange is completely clear of any bass coupling issues with great imaging and focus. If you play this song and find the bass to be lumpy, bloated and with lot's of overhang and Jennifer starts to sound like she is congested or has a cold, you know the speakers need to be better positioned as the article describes.
The other point here is that my room has ZERO acoustical treatments at this point yet with good speaker positioning the sound is still relatively speaking quite enjoyable.
https://youtu.be/1zvy1Knk0TQ