I think he’s doing this in Vancouver:
Down-Hammer-Down on the lower string
Up-Down-Up on the higher string.
The issue is that there is no exact repeated pattern that he executes in one way in “Girl Gone Bad” or in “Spanish Fly” or in the fast “Spanish Fly” sextuplets in the live solos.
For me, the Down-Hammer-Down/Up-Down-Up thing works perfectly, for me, to execute the guitar/drum riff from “Girl Gone Bad” with a repeatable pattern that captures the feel of what is going on, if not what is actually happening…because I can’t figure out exactly what’s happening. I feel like my compromise pattern might be what he is actually doing in that part in the Vancouver clip. This pattern also works very well for some of the sextuplet licks in “I’m The One”.
The “Spanish Fly” sextuplets are even more mistake filled and random. I can only use my own “compromise” repeatable pattern that gets the overall sound, feel and timing close…because what is going on in the recording of “Spanish Fly” is so “un-repeatable” and has no pattern in itself. Same for the live sixes during the live guitar solo segments.
The best I’ve come up with for these “Spanish Fly” sextuplets is to actually play:
Down-Hammer-Down on the lower string
Then a strong, “pushing” Downstroke to the muted higher string
And then “Up-Down-Up” to complete the licks on the higher string.
Ultimately, whatever anyone plays for these parts is bound to be a compromise, because no one can figure out how to play exactly what’s going on note-for-note. If it baffles even Troy, then I’m lost!