I am not completely sure of the issue. If I understand correctly what you are trying to do, bury the chafe cover at one end and just leave it out at the eye and whip it to the rest of the line at the eye. If you want ultimate strength, just whip the chafe guard at both ends. In other words, leave a few inches of chafe guard out by passing the core through it, then whip it to the line.
Very good. if i have room for the entire core dependent covered eye on the old shivs, I will do it HW's way. if not, then Allen's way. I plan to have about 2' of chafe guard on the spin halyard. but not sure how little I can get away with on the genoa and mains. I bought enough rope to redo or end for end if the shivs are horrible.
allen, if I whip down the chafe, should i do some lock stitches along the length?
While adding dyneema chafe covers is a good thing to do and I do it on a lot of lines, Samson MLX is a pretty low tech line and seems like a lot of effort on a product which is not really appropriate for upwind halyards on a race boat.
I would recommend making a full covered eye with chafe, or burying both ends of the chafe, as a spin halyard will quickly eat through whippings to move the chafe cover. Chafe cover also does not add really noticeable bulk at a spin halyard sheave.
Chris, the boat is a '75 1/2 ton of good heritage but it will not be raced a lot. The warp speed was 1.5x the price. I am not going to put dyneema covers on the halyards. just a bit of the original. the current halyards are 1994. lets just say you don't get out of bed on a bad day for my annual boat budget. If I can get a few lb.s out of the air and make it last more than four years I am happy. As for the effort, its good to learn new stuff when one is old. I still have one wire if the MLX is too stretchy.
I am running Amsteel in a wire shive. That is why I came up with the special splice that keeps the splice out of the sieve. It has been up there for several years. I did move the splice down once though but that was mainly to get clean line when I put the new knot on. http://L-36.com/HybridHalyard.php