We have an aluminium boat, which is fairly heavy, so I assume the hull does not deform under rigging stresses
Milvina is 47 ft, carbon mast, with 3/8" head stay and backstay, Most shrouds also 3/8"
Rig is 9 years old, so I thought well stretched and stabilised.
We set the rig up last with a Loos gauge to 15% of the wire's breaking load (On the advice of a rigger in Germany who was kind enough to lend us his gauge)
I get the feeling that the headstay is not as tight as is was when we set the rig up last, but have no way to measure.
Any ideas on how much stretch is normal? Milvina is 47 ft, carbon mast, with 3/8" head stay and backstay, Most shrouds also 3/8"

On a more general question. how much sag should we see looking up the headstay while close hauled in a stiff breeze?

Thanks for the usual practical wisdom offered by the denizens