Old Tom here...........Sure, the 7th green complex IS pretty special, but, there are somewhere south of half a million greens on the planet, so it MIGHT BE A BIT OF A STRETCH to be able to pick the best, don't we agree? All this is mostly 'eye of the beholder or player', stuff, IMO, for as we all might consider ourselves to be 'experts', well, at the end of the glass it is pretty subjective.
And even on the ten holes open at OLD MAC, the tenth green complex is pretty darn sweet, as is the road hole, #11(it 'works' fantastically well, IMO). I don't know that the 7th (though it is certainly dramatic, an exciting play, and a great vista) is 'better than' those two, in terms of the golf shot required into, and the play around and on the putting surfaces.
As to whether the 5th/10th constitutes a double green, well.......they are mowed as one, though the isthmus that connects them is narrow, and the character of the two complexes are not similar, as we might think of most double greens to be. The designers, shapers, and supt. would have to share some inside info on that one.
That's my two cents!
Best,
Tom