Nick, I would think you could easily do this with three registrations on your S-970. Yes, it does begin with Tango then seems to go into some sort or Rumba and eventually into a light swing style before returning to a Tango, yet maintains the same tempo throughout.
Good luck,
Gary
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PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!
K+E=W (Knowledge Plus Experience = Wisdom.)