If it is a modern design the shrouds will be rod, and probably 1/4” or 6mm. Only if it has a really large sail area for its size, think Farr ( old Mumm) 30 might the highest load segment be 8mm. That would probably be V1 for multiple spreaders or D1 if single spreader. You will never see the headstay as it will be covered by either the foil for the jib luff or the roller furler. The backstay can be either rod, wire or both depending on the type of adjuster. All will terminate in some sort of tang to attach to turnbuckles or other adjusters.
Running backstays or checkstays could be wire or now more likely pbo or Amsteel synthetic. These will be lighter and lower stretch than wire.
When in doubt go for the cleaner, lower windage/drag solution.
