(cont): Here's what I use on Attack from Mars:
jib halyards: 5/16" vectran
spin halyard: 5/16" spectra
main halyard: 1/4" vectran (yes, this seems to work fine)
jib sheets: 3/8" vectran
main sheet: 5/16" tapered down to 1/4" for the tail.
I use normal size harken cleats for most purposes, spinlock line
clutches for the halyards. Use aluminum cams for any cleats that get
high loads or lots of use (mainsheet, spin halyard).
The back and fore-stay fittings should be more carefully calculated.
Start with the breaking strength of the cable itself, and do all your
computations based on that (ie, use fittings with higher breaking
strength than the cable).
I'd be happy to answer any questions--I rerigged everything (standing
and running) on Attack from Mars and have been very happy with
everything.
--Brendan Busch
Attack from Mars