Bit late to this but may still be helpful for someone else. I felt like I could go half a size down in the Sirius compared to the old dragons. I have a pair of Sirius in the same size as my old dragons and after a few sessions they have stretched a bit too much, so much that I would definitely go half size down if I were to buy them again. Still a good shoe though! Due to them bagging out more than expected, they have become weapons for smeary, slabby indoor problems, probably not what they have been designed for though!