We raced and cruised for many years on a 36'' boat with wire/rope halyards as you propose, with the rope tails led to a bank of stoppers on the cabintop so the splices were fully loaded. Never saw any sign of distress. These were commercial tapered splices. Is there any way you can fit sheaves to take the new, small diameter Spectra lines? These can be spliced to a larger tail (and/or sleeved) so the stopper will hold them. Lighter - and no nasty meathooks.