"DSK" wrote
I guess more boats are more poorly built than I realize.
Most of the boats I have experience with, including our 22yo
36' Taiwan-built trawler, have very little or no deflection
when set up on jackstands, and no need whatever to
"settle."

A Trawler? I thought this discussion was about sailboats!

Sailboat rigging does bend the boat and when stored, the hull tends to
revert to it's original shape.

It is impossible to put 1000+ lbs of force on the forestay and backstay and
not have the hull deflect. Fibreglass laminates are elastic, so do bend and
the bend releases when the forces are removed.

Wooden sailboats (especially those with long overhangs) when stored with
mast down, used to settle unless the bow and stern were supported. If this
was not done, the rig tension would open up the seams, especially around the
keel. Fibreglass boats may settle a bit further due to gravity if stored for
very long periods but not much. Important though to have weight on keel and
not on supports which may deflect the hull under pads.

One other thing. The temperature has an affect on rig tension - both on
thermal expansion and on elasticity of metals and hull. Aluminum expands
about 30% more than S/S does. In addition, these metals and the hull become
LESS elastic as temperature rises. It's a complex mix of affects! If the
rig is set up in cold weather, by mid summer the tensions will be different.
Just keep watching the leeward shrouds and tighten up when need be.