Looks like they would work just fine. I'll be making a set of those some day. That would make a nice fuller, is it 3/4" rod? Hard to tell from photo - might even be 1" or larger.
Here is the squaring dies I finished today, I took a 1-1/4" OD square tube with 1/8" walls, cut in half to make two angle irons. I then filled the space with a railroad spike and weld, then welded to flat plate for die base. Not pretty, but I think it will work.