IWC Schaffhausen SPITFIRE MARK XVI Mode D'emploi page 25

Determining bracelet length
22 | 23
Place the watch with its separated bracelet on your wrist
and estimate the number of links you need to remove
(as described above). If you need to shorten the bracelet
by several links, you should remove the same number
of links from each half of the bracelet, if possible, to en-
sure that the clasp can be worn more or less at the centre
of the wrist. Keep the surplus links and the separating
tools safely for use in subsequent adjustments.