I have long wondered what size I should order. I usually have shoe size 40, only in exceptional cases even higher or lower number.
Ordered in 39 because of the reviews, the shoes, which was also good. Even in 39 sit shoes still relatively loose, so I've inserted a thick sole. Now you perfectly. I think I even a 38 would have fit.
So I definitely recommend trying one size smaller. At least if you want to wear the shoes barefoot.
