02-03-15: Geph0007I suspect that "or Oval 12" was a typo, and should have been "of Oval 12." If so, consistent with what has been said above and in the other threads I linked to I would expect the answer to be speaker, system, and listener dependent, and essentially unpredictable.
OK let me ask this One run of AP Oval 9 with jumpers or bi wire (two runs) or Oval 12?
Something to consider, though: Two paralleled 12 gauge wires have the same resistance as a single 9 gauge wire of the same length, so two paralleled runs of Oval 12 presumably have (to a very close approximation) the same resistance as a single run of Oval 9. And two runs of Oval 12, whether purchased as a biwire cable or as two individual cables, cost significantly less than a single run of Oval 9.
So it might therefore make sense to purchase the two runs of Oval 12, either as a biwire cable or as two individual cables, compare the resulting sonics with and without the jumpers in place, and go with whichever of those two connection arrangements sounds best. Without the jumpers you will have the 12 gauge biwire configuration you referred to. With the jumpers and the same cables you will have, at least in terms of resistance, the equivalent of a 9 gauge cable.
02-03-15: Jmcgrogan2My guess is that Michael was envisioning that there would be an odd number of half-baked answers, plus one answer that is 1/6th baked. :-)
Not much to add to these three excellent answers. I would only question how Michael came up with two-thirds of an answer. ;^)
Regards,
-- Al