Rolf,

Do check that the cable thimble and the shackle are compatiable, the bolt eye of the larger shackle needed for 3 stays ( 4 in the case of an A Class rig )will be a tight fit through the 3mm thimble as I discovered.

The other thing I found using SK75 was that under load the Brummel knot locked it off beautifully but under very light loads with slight " jarring " effects, the knot would gradually slip through ( the rope is quite slippery and naturally oily to touch ) and eventually release ( as I also discovered ), I found that simply sewing a couple of loops through the tail section stopped this.

Do check the breaking strain as SK90 is about 1.5 times stronger than wire and you can afford to go down in diameter, I found the larger 4mm seemed to stretch /creep more than the 3mm and sort of reasoned that on first use, the smaller diameter " tightened " the weave of the new rope whereas the 4mm never seemed to really fully close the weave.