Sizing is true based on mass-market brands. If you generally wear an even size (i.e. 10 US) make your sizing decision based on your foot width. If you have a more slender, narrow foot, order the next half size down, if you have a wider, high-volume foot, order the next half size up.
The lasts we use to build our footwear are slightly longer than traditional lasts and will allow you to order the next 1/2 size down without issue.
Your pair should fit snug out of the box, leather will adapt and form to your feet over time.
Email firstname.lastname@example.org with further questions about sizing.