Put on your old turnbuckles,,,, What, you threw them away, never ever throw anything away sometime in the next 50 years you might find a use for them.
Buy Norseman terminals for the lower end, cut off the existing terminal, install the Norseman's and Bob's your uncle. Make sure you've got enough extension in your new turnbuckles to fit with the shortened wires. If not, toggles will cure that problem but an additional expense.
Unless the head
stay is really really really slack, shouldn't be a problem sailing the boat. Won't point for beans because of the belly in the wire but should be okay.