Total yield thusfar: 1.55%.  This has been largely pulled with the same amount of limonene each time.  After about three separate pulls, SWIM doubled the amount of limonene by adding to the limonene in use; that, using larger amounts of vinegar, and probably time, boosted SWIM's yield significantly on his second to last pull.  He suspects that this last pull was about the last he'll get, but he'll try at least one more.  Vinegar's quite cheap, so why not?