I bought my first Birkenstock, the new Madrid big buckle in size 4, 240mm narrow. Unfortunately it’s too small length wise as my toes are on the edge but it fits perfectly to my feet’s curvature to a point it makes a squeaky noise when I walk. I then ordered a new pair in 245 mm and normal width but it’s far too big and I can’t walk in it. Does it mean Birkenstocks aren’t for me? 😢. Not too keen on Arizonas.