5. Is it true that Scaler is this spreadsheet on steroids? If so, is that how you build chord progressions?
Essentally, yes. But the Circle of Fifths is only a high level overview of the topic. In fact, I keep a copy on my Wall as a constant reminder. Scaler on the other hand, is a complete research tool that goes well beyond this simple illustration. It encompases a graduate study in regards to music theory associated with Chords and Scales. In my early education I learned that, "scales are chords and chords are scales". In other words, "there is no difference between scales and chords". Scaler intergrates these all this to fully confirm this concept.
But then Scaler does further in terms of creating midi and accompaniment. You may or may not have any use for this secondary feature set. But it does add some fun to hear any of the scales and chords which it can present.
4. My and your info both seem to agree that the Amaj chord is not in the Dm key, yet the Amaj sounds good to me and presumably others. Not sure if I understand this.
It is common to hear a major/minor substitution in a chord progressions. Only one note changes (the third) which is very often heard in bluesy numbers. So you are not the first to create this sound. My thoughts were that placing this specific substitution at the end of a phrase with no resolution may be a bit odd. But I honestly did not hear this during my listen so I trust it sounded fine as you played it.
Good questions. I hope my rambling is helpful. I suspect it may be best if you and I did a screen share some evening so I can show you a bit of how Scaler works. Otherwise, there are no end to the videos on line. But I may be able to save you some time. Fact is all that you need is in any good Theory book, but what fun is that?
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