It's almost impossible to measure the circumference of your own feet, which should be done by a fitter while you're standing and sitting but not bending over which will alter the pressure on your foot. For instance, I wear Graf Edmonton Specials and love the lower heels, which are comfortable for my high arches. But my slightly wider left foot measures 6.5.cm across the sole at the ball of the foot and 17.5 cm in circumference at the same place. Which measurement did you mean?
I'm assuming that's the width across the sole at the ball? Whether that's too wide for Graf I guess depends on the size of the boot you were trying on. Mine are semi-custom to my measurements and came labelled as s 2 SS (Super Slim). The regular sizes without customization are larger. I hope you can get a Graf that fits, since I think you'd love them. So comfortable!
@Ic3Rabbit suggested I try them as a change from my usual Risport RF1 boots and I'm happy with them.