Very easy process.
John:I did this on my '85 H'31 in the last year or so. I called Hunter for the correct sizing. I then ordered the lines from JSI w/shackles. I ordered my lines a little longer incase I wanted to bring the line back to the jib winches.When the new lines arrived, I cut off the old shackels from the line and sewed the bitter ends together (end-to-end) with whipping twine. I then put a couple of wraps of rigging tape over the joint and just pulled it up, over, down and through. There may be a little tug that you will feel when it goes over the sheave but no big deal. Cut off the tape and whipping, clean up and you are ready for another brew.The entire process for three halyards was less then an hour.