Jake,
I assume you are referring to this Marlow line?
http://www.apsltd.com/c-1500-super-pre-stretch-marlow.aspxIf you're re-coring, just do both ends with the Marlow in the middle, so mostly amsteel is touching the spinnaker and no more burn holes. I know 2 splices instead of one. I think I could have gotten away with the FSE Robline Racing sheet as a cleat point if I buried the tail of the amsteel further so the cleat was on racing sheet+amsteel. That is what I will try next once this halyard wears out. Currently it's doing well with a polyester cover over the racing sheet in the cleat area.