I just went through this. Dog is right, about the dyneema, but again, you have to get to the top of the mast to inspect & maybe replace the sheaves (unless you plan on unstepping the mast).
I understand your concern about eyes or swages, but what's wrong with a splice? I thought the whole purpose of a splice was to make a connection that was as strong as the original rope?
How high up is his light? If he's not running one of those combo units at the top of the mast, perhaps he can reach it by putting a ladder on the deck, against the mast. That's not my preference, I've just heard of it being done.
I understand why wire halyards came into play, they just seem like a bad idea.
S/V Old Shoes
1973 Pearson 30 #255