Here''''s another what should
Everyone has 20-20 hindsight. But what would one do if the halyrd was lost? If it were my privately owned boat, and I was planning on extensive cruising, I would probably rig and leave in, a messenger. It would need to be generic in nature, in that it is not specific to a particular halyard, which would make it a bit tricky depending on the masthead sheeves and the ability to route whatever halyard you wanted through the proper one.
If you were chartering, you are lost if you do not have the minimal gear needed to rig a temporary halyard. You would need a block (A good sized snatch block will do), lashing, and a length of line for the halyard, not to mention a methode to get to the masthead. Go aloft, rig your block near the masthead, lashing it to the both the backstay and the mast, being mindful of chafe. Reeve your temporary halyard through, leaving it outside the mast. Now you will have the additional windage of the outside halyard and the additional weight aloft. But then again, this is a jury rig to get you through until you can get to port and achieve a proper repair.