Go with the bigger one. In the summer it will move and stay on your finger. In the winter, do what I do, I put my super thin platinum band as a guard over it. I don't like the feel of rings that are snug... it makes my finger look fat!
If you find down the road, your ring is too loose when in your new environment, the jeweler only has to resize one of the rings, not all of them and you would get a more precise size say within a 1/4 size. One ring is all that's needed to hold the trinity to your finger while the rest remain a bit loose. This is only a suggestion (not sure what Cartier does)