No one mentioned this butIF you do deside to do your own welding with that rig (which I think would work if you know what your doing) is to make sure the surface your welding is very clean NO RUST in welding area. I've seen people lay a beed that should hold up the Sears Tower but falls apart because they didn't take the time to grind away the rust. No one was born a welder it takes time and practice try welding an old frame section if your replacing the rear frame member that should give you plenty of material to play with. Weld two pc. together then cut them apart with a saw or grinder to see how your penitration is. GOOD LUCK. You'll never know if you can if you don't try.
Charlie