I would purchase the ring where it best fits on one finger, otherwise, you will have an odd fit trying to do a "one-size-fits-two". I find myself always wearing my rings on the same finger, the ring finger. This ring pops, and I personally think it pops the most on the fourth finger, a nice bold look.
This is me, and only me, but I find bold rings on the index finger not elegant. They also create a stumpy look. I also do not like the middle finger because it IS in the middle and the shape of the hand is a lost. A ring in the middle finger also highlights the middle finger which for many people is also the fattest finger. So for a big blingy but elegant ring look, I like the fourth finger best... it adds a bold look and highlights the hand. I think two long fingers (index + middle) with a bold ring on the fourth finger makes the hand look slim, youthful, and elegant. That's just me to share my two cents of course.
As for size, I size my rings to fit when my fingers are the fattest which is in the summer or after a salty meal. As it is winter now, I would suggest eating a salty meal (sushi?). When I do that, my fingers are fat the next morning, and that is when I test out any new rings. As a matter of fact, I just recently did that with a VCA ring. I could not decide on a size, so I bought two sizes, ate a salty dinner, woke up and tried on both rings. I knew instantly which one I would keep and which I would return (I kept the looser one). I do realize all rings will be slightly loose in the winter, but I would rather have a ring on the loose side vs. the tight side. The dreaded tight "muffin-top-finger" look is not a pretty sight. A ring slightly looser will make the finger look thinner and more elegant. You can see VCA photos or other modelling photos... rings are always slightly on the loose side. No muffin-top-finger ever.
I hope that helps. Just my two cents of course to help you decide.
Congrats on your new ring. It's beautiful and bold... I am sure it will be gorgeous on you!
