How many books by the great masters of jazz pedagogy would you like me to list?
Don't choke on your list.
BTW on Spain the second chord (F7) is a secondary dominant. it has a very unique sound, and just playing a selection of common tones over that chord insults the song. Really. Listen to it. Do you hear that? Can you tell what note in the F7 is really unique and should be emphasized?
Ugh.
It's an F#7, by the way. The Dominant Seventh of B Minor, so it's probably NOT a secondary dominant, but rather THE Dominant - I think I covered that already. And the "unique" note (whatever that means)? I'm presuming you are referring to an A# - it's also in the melody.

Maybe not really that unique.
not "mashed potato[e]s" of some 6 note common tone scale.
Firstly, I suggested a
Tone Collection comprised of the notes of a B Minor Scale - that would be SEVEN notes (B, C#, D, E, F#, G, A, B). Secondly, I suggested a FIVE-note scale - B Minor Pentatonic. I also suggested utilizing the A# over the F#7 chords as well as chromaticism.
I would like to know where you learned about improvisation? Who did you learn from? Where does that person teach? I ask because the common tone approach is really a way that alot of "learning" improvisors get by, and if you were told that NOT digging deeper into the harmony and being more specific (ie using chord scale relationships) is OK, then you've been disserviced.
Don't worry about that.
Look if you want to name a bunch of scales and modes for every chord change, go for it.
Back to "Spain", what Key Center should we pick? B Minor? That's the one I prefer.
Let me clear these scales/modes with you:
G Maj7, so that would that be G Lydian?
F#7, would be F# Phrygian Dominant? Are we are "temporarily" in B Harmonic Minor? But I wanna hear some -/+9's! Gimme a G##!

An F# Half-step/Whole-step scale ain't gonna work.
Em7, would be an E Dorian?
A7, would be an A Mixolydian?
DMaj7, would be a D Ionian?
GMaj7, would be a G Lydian?
C#7, I have NO idea. Wait, maybe the V7/V7? But that assumes we are indeed in the key of B (major/minor?). I think I'm hearing E#s, A#s in the comping (from the record), but the melody seems to still be in B minor, I'm lost, this is so confusing. Better get out one of the books on
the list for the answer. Alas, to make it easy, I'll just fall back on my "learning" improviser's boring ol' Tone Collection and perhaps work in an E# too impress - but, darn it, I like those -/+9's.... Ooh!!! Maybe a C# Half-step/Whole-step scale (C#, D, D##, E#, F##, G#, A#, B) could also work. Man, that would be impressive! But I kinda like -/+9's, +11, b13, too (D, D##, F##, A) extensions - geeze, back to my Tone Collection.
F#7, dang that Dominant Seventh chord again! Must be in B Harmonic Minor - but who knows. I'll get that F# Phrygian Dominant going again - since I'm hearing a b9.
Bm, Ah... feels/sounds like some sort of resolution - maybe we
are in B Minor. Where is my music library, for verification?
B7, Dang another borrowed Dominant? Must be the V7 of E (Melodic) Minor, there must be some sort of music theory explanation for this

Ah, this MUST be one of those Secondary Dominants I've heard about! So do I use a B Mixolydian b6 scale (there is a D# in the melody)? But I might want to hear a +9 (C##, enharmonic of D) to help get back to the first chord (GMaj7), after all, this last chord is really just a turnaround. Isn't it?
Dang, I have a headache.
But wait, what about the melody? A Tone Collection of
these notes: B, C#, D, E, F#, A are ALL found in the melody... hmm, I might be onto something. I could add a G to this Tone Collection, it is a chord tone to MANY of the changes - GMaj, Em7, A7, maybe even an extension to F#7(b9) and C#7(+11). Too heady?
And, as i stated in an earlier post, utilize the A# (the "unique" note) on those groovy F#7 chords.
So in an effort relieve the headache brought on by that ridiculous list of scales/modes that redundantly have many of the same notes, I can utilize throughout, a Tone Collection made up of the notes found in B Minor Scale. Which is what the melody is drawn from.
... when I go back and listen to Chick himself solo on that tune, I really hear each chord going by
Yah, I do to. And chromaticism - those pesky notes that aren't in your scales/modes requirements.
If one feels the need to make endless lists of scales/modes that have their tonic based on the root of a given chord - do it. I used to. It was fun for a while.
Then I realized that I was needlessly reorganizing the same group of notes and labeling them as modes, when in fact I was never actually in those modes.
For the record, I hear "Spain" in B minor. That's it, one lil ol' mode.