Christie's. To be honest I'm now kind of regretting the purchase (haven't even seen it yet!

) because I was so excited that one was available, I got too wrapped up into it without thinking it through. I do not know how it will fit (all my VCA rings seem to be different sizes, even if on the same finger), it is not returnable, does not include COA, and I hate the 25% commission fee you pay on top of it.
Then I found one listed on VC that is probably a better size, with documentation, returnable, and no upcharge (though with taxes and customs fees it would still be priced ~2.5K over what I paid at auction). This experience (good or bad) will definitely inform future purchases. I'm not typically an impulse buyer.
Supposed to arrive tomorrow and I will post pics.