My heel to toe is 27 cm, I bought size 45 which is 28 cm heel to toe. I bought bigger so I could wear light running socks with them. As you can see from the photo the exact measurement is 28.5 cm which gives plenty of room for my toes. They are wide enough to accommodate my foot at the widest point which is 24.5 cm. If it helps I fit perfectly into Saucony running shoes and Salewa hiking boots.
There is no heel to toe drop just a flat sole.
There good enough to walk around in hot weather but with no heel support and thin soles I would not wear them hiking.
Over all I like them, I will review them at a later date to see how they hold up with time.