Adding a spinnaker halyard spectacle

The boat is  Viper 830, the mast is carbon and I have a fractional code zero I would like to fly from a masthead spinnaker halyard that stops at a spectacle just above the fore-stay.  My reason for doing it this way is I have the ability to run, two mast head spin halyards, rather then add a sheave box above the fore-stay.  Any thoughts or experience doing it this way?  What should I use for a spectacle to stop the halyard above the fore-stay?