Thanks for the figures! This is really good. I swear the refractive index was nowhere on the hive before this I searched everything. I even look up the reference books in library. Now basically swim can do rxn, use bisulfite, metabisulfite, steam distillation, and/or fractional distillation and then know that basically the closer to 1.540, the better. Here are nD's of common contaminants of ketone as listed in Sigma-Aldrich catalog.
Isosafrole: 1.5760
Safrole: 1.5370
Isosafrole, for example, the main contaminant after a Wacker, is much higher nD than of ketone, so you could tell by if your nD of sample is to high, then must have too much isosafrole, right?
About importing, probably swim thinks it would be very risky, especially at those huge volumes you say. Better to make it home-made and check and purify as much as can be dones.