We also sell the stock replacements (if you have the arm with the curved tip?) here:
https://www.wildhorses4x4.com/product/Wiper_Blade/Bronco_Wiper_Parts
That's great if you want a stock restoration, but I think upgrading the actual arm to a spade style that a normal snap-on blade fits is better. You can get longer blades and source them locally (usually) for less money each time (also, usually).
But money-wise, yes just a refill for the blade is likely still very inexpensive when you can find the right material.
Good luck whichever way you go. I installed the different style arms to take the normal blades years ago and never looked back. Can adjust them to fit perfectly.
In my case, I even went one size up on the blade over what actually fit, so that I had to trim a slight curve into the end so it fit over the windshield gasket without distorting or eventually tearing. This was just to get that tiny bit of extra blade at the other end.
Paul