You can find various versions of this sandal on the web but I wanted to bring in some design and construction elements from the perspective of a shoemaker.
Send these to me with a check for $75.00 + $8.00 Shipping (if USA) and I'll make you up a pair!
Trace each of your feet. Mark the point between your big and second toe (where the strap should come through). Mark your ankle positions.
Be sure to hold your pencil perpendicular to the paper.
Another view