Cisco I have often read your posts on here and thought you had a great depth of knowledge of most things sailing but you have just confused me. Highly possible I have got this whole thing the wrong way around so apologies in advance.
But ....
If you were to attach the new dyneema to the rope end of the existing halyard and pull it through (ie pull it up and out the masthead by pulling the wire end) won't that mean that when you get that join back on deck after going up and out the mast you will be holding the dyneema (rope) end with the wire end of the new halyard at the mast? ie the wrong way around?
I am assuming that the wire end should be the bit that attaches to the head of the sail such that when the sail is hoisted the rope/wire has been pulled through to the winch so that halyard stretch is minimised while the sail is up and the rope end (easier on the hands whilst hauling it up) is the tail?
Again maybe I have misinterpreted something that should be obvious (it's been known to happen).
On a related note - If you are using Dyneema rope for a halyard is it still necessary to have the wire spliced onto the end? I thought the attraction of the new ropes like Dyneema was that they negated the need for this and therefore saved on weight aloft?
See Len76 - I've been sailing all my life and still learning