....If the cover is coming off any way, measure the rod sticking out of the clutch pack.
12.5mm is about the maximum rod length.  13mm is definitely too long.
as proposed (and I agree) the rod and cable lengths are more likely to change than the clutch plates.
If the rod length is less than 11.5, time for a new rod.

Also, I prefer to have a full radius on the ends of the rod.  Promotes smoother action with the sintered actuator cam.  Also spins better.  But rounding the corners effectively makes the rod shorter.  Which is why I like the max length rod sticking out.

And the more rod you have sticking out the more effective the motion is.