Rig Tuning

Shane Grover, of Seawind, wrote a technical article in June of 2021 that outlines rig tensioning and tuning that is specific to Seawind catamarans.
Technical article: File:Rig Tensioning and Tuning.pdf

I have also discussed the topic with circumnavigator, sailmaker, and rigger Jamie Gifford who as provided the following additional advice on the differences in diamond stays and shrouds tension:

1. Catamaran rig tuning - BIG tension in the diamonds induces prebend creating a stiff/stable mast section
   
2. Shrouds and headstay have much less tension. Over tensioned shrouds compresses the mast into its base structure and lifts the hulls. That can change hull shape affecting things like doors opening/closing or compressing the mast step structure.
   
3. Reaching and upwind, very roughly around 15 knots of wind and higher, the leeward shroud will become loose/floppy due to normal shroud wire stretch. This is not a rig tune problem.