Can someone explain how a fence stretcher works? Can one person use it or do you need two people? I have the wooden posts in the ground and need to put up the 2 x 4 horse wire now. I am a woman and on my own....but I am strong. Is this something I can do by myself? Also is it best to buy a stretcher, or is it possible to make a good one? Thanks in advance, I appreciate all your help!