Tom P. in Evant, Texas, my ranch neighbor, skins his hogs by first hanging them up, making a one inch slit on the top just forward of the tail, sticking 150 pound shop air hose into the slit on a long air needle and inflating them. Pulls the skin right off the meat. Craziest thing I ever saw but works very well!
I use a diamond blade knife. Costly but works quite well on these pigs and goes quite a ways before dulling. Then I send them back to Denton, Texas where they make'm and they put on another edge for me for the cost of shipping back and forth.