I tend to flucuate btw a 7 and 7.5 in Seychelles. I have tried on many, many pairs of Seychelles and I think it depends on the style. For instance, with the Habit Forming, I got a 7.5 but would have been happier with the 7, I think. Just for reference, I wear a 7.5 in Nine West.
I have a few pairs of Seychelles shoes, and some of them run TTS and some are slightly too roomy on me. I'm normally a 10 but in Seychelles round-toe styles a 9.5 would've probably been a better fit for me.