The lanyard spacing between dead-eyes was 5 times the diameter of the dead-eyes, 4 times was somewhat common and infrequently 3 times was used. I believe the dead-eye lanyard spacing of 3 or 4 diameters was used on some smaller ships that did not have high rise sides and tall, thick, lower masts. Their purpose was to adjust the tension of shrouds that change with the temperature and humidity variations. They are considered running rigging and are not tarred like the standing rigging. The dead-eye diameter was 1/2 the mast diameter. If this did not come out even, the next larger size was used. On the upper mast it appears that sometimes the next lower size might get used if it was closer to the half diameter than choosing a larger one.