We drill holes in our timber split posts and feed the barbed wire through each post in turn.
Bore a 1¨ hole at right angles to the line of the fence and bang a wire roll holder for the barbed then feed a long gal multi-strand wire through the holes from the other end , attach barbed wire to it and pull with the tractor
Definately do the top first or every strand gets hooked up and hands get lost like that.
When i put in wood post then 2 Gal ´´T ´´stakes then wood etc I have to feed the multi in the bottom first to give a line to bang the gal posts in. I never pull barb in at the bottom first