Does this question make my pocket protector look big?

So today, on my way to work, while stopped and waiting for the pilot car (the five Alaska seasons being fall, winter, breakup, spring, and road construction), a question popped into my head:  in the famous Paul Desmond piece “Take Five“, would it be more appropriate to view the descending turnaround as belonging to the song’s root (minor) tonic, or to its relative major as a temporary replacement tonic?  This is just an attempt to better understand how to think about the written sequence of chords.  I think I talked it out of myself at the time, but I’d love the opinion of those more formally versed in theory than I am.

(Yes, I think geeky things at weird times.  It just seems to be the way I’m made.)

Okay, so I’ve studied the piece a bit before, even going so far as to score it up as an arrangement for Guitar Circle Colorado, transposed up a half step into the more convenient E minor.  (What follows is based on that Em arrangement.)

The vamp is written as Em – Bm7, which is a natural minor thing, written with one sharp on the staff.  The turnaround is written as:

Cmaj7 – Am6 – Bm7 – Em7 – Am7 – D7 – Gmaj7
Cmaj7 – Am6 – Bm7 – Em7 – Am7 – D7 – F#m7 – B7

It occurred to me that one way to think of this turnaround sequence would be within the context of the Em as the tonic chord, in which case I’d think of the chords like this:

VI maj7 – IV m6 – V m7 – I m7 – IV m7 – VII 7 – III maj7
VI maj7 – IV m6 – V m7 – I m7 – IV m7 – VII 7 – II m7 – V 7

Hm.  That somehow doesn’t seem right–more like a shoehorn than a natural fit.  But what if I looked at the turnaround as belonging to the key of G–which would be, after all, the relative major of E minor?  Then I’d think of the chords like this:

IV maj7 – VII m6 – III m7 – VI m7 – II m7 – V 7 – I maj7
IV maj7 – VII m6 – III m7 – VI m7 – II m7 – V 7 – VII m7b5 – III 7

Well, that seems to clean up a lot, doesn’t it?  4-7-3-6-2-5-1 would seem to be rather precisely descending in fifths, and the idea of the last four chords being a two-five on G followed by a two-five on Em…finally sold me on the idea.

Okay, so that’s what occurred.  And the question to those more formally schooled in functional theory than I:  am I thinking properly here, or am I missing something obvious?