Your droning note - great! One suggestion. Instead of playing over the droning note play over a modal vamp of the tonic chord and then one more chord with Dorian's characteristic note in it's makeup. Dorian's characteristic note needs to be droning in the vamp - much more so than the tonic. Why? To sustain the Dorian mood. What note is that? Dorian's characteristic note is the natural 6. So which chords in the Am key will have an F in their makeup?
Bm7b5
Dm7
Fmaj7
G7
You will always have at least 3 candidates. I'd discount the diminished chord and the Fmaj7 and try the Dm7 first. How do you like Am///|Dm7///|Am7///|Dm7///| etc. etc.
See what you think of the others, perhaps Am///|G7///|Am///|G7///| Which do you like best.
This comes from
http://www.riddleworks.com/modalharm3.html
Now playing the C major scale aka Ionian -- Ionian IS the major scale it's not really a mood of the major scale it IS the major scale --- so your vamp may not work here. C is a tonal center you are not dealing with a characteristic note so just a plain ole I IV V progression and the C tonal center may be best here.
This may be a paradigm shift see what you think. Don't get side tracked keep going.....
Modes in every key -- this helps me.
Major modes
Ionian same as the Major Scale.
Lydian use the major scale and sharp the 4 - yes, it’s that simple.
Mixolydian use the major scale and flat the 7.
Minor Modes
Aeolian same as the Natural Minor scale.
Dorian use the Natural Minor scale and sharp the b6 back to a natural 6.
Phrygian use the Natural Minor scale and flat the 2.
Locrian use the Natural Minor scale and flat the 2 and the 5.
Yes those are the characteristic notes.
Have fun.
