Finished it this lockout (back on Tuesday), with 13 Runestones... only needed 2, got 1 from Iron Qon, Twins, AND Lei Shen (then had to re-queue for Lei Shen to get his heart afterwords).
I had a few Runestone-less weeks in the mix. But now, I have the pain that is the Wrathion Challenge, Melee DPS variant, with a 517 ilevel on my Ret spec.