Can anyone give me some insight into sizing for the Sexy Thing Cutout Heels and the J'adore Elaphe Heels? I tried on the Sexy Thing heels before and I think I was a 38.. can't remember.... but everyone has been saying go up half a size. Does that mean from my American size or my European size? I wear 37.5 for Jimmy Choos and Louboutins (if that's any help). Should I size up to a 38? THank you in advance for the help!