Our J/109, in common with most boats with spinnakers, has turning blocks for the sheets that must reorient to loads from different directions, depending on the point of sail, and therefore uses loose blocks on pad eyes.
The problem with this is that spinnaker sheet blocks tend to bang on the deck with motion, in use or not.
Stand-up springs won’t work because they are always trying to force the block into an upright position, so will mess with the lead angle, particularly in light air. Ditto shock cord to a lifeline, which is often used.
Neat solution!