twice now. I don't know if this will help but until you get other info,..
I have a longer than needed cable cut and have the rigger fix an eye on one end. That connects to the lifting screw on the cabin top.
With the boat in the travel lift slings in the yard, we drop the board to the full depth(visible by growth, wear, can be marked too), then fix the board there with blocking on the ground. (at this depth in the slings).
Next we snip the cable at the nicro press loop and thimble that attaches to the fitting on the board in the photo, 2 rivets and bronze plates.
Disconnecting the other end at the lifting screw on the cabintop, we pull the old cable up through the centerboard trunk and piping chase to the screw.
Next, we feed, in the reverse direction, the oversized cable from inside the cabin until it comes out the slot below. Then we bolt the new eye on the lifting screw and leave the screw to it's lowest depth/setting in the cabin.
Then it's a matter of putting then new thimble on the board connection, running the cable around it and a new nicro press, get it set to the right height, and clamp.
Having done it a couple times, it goes quickly, 10-15 minutes or so.
You boats linkage will be entirely different but you may be able to do something similar if you can't get an exact measurement.