The 4 1/2" angle grinder with a cutting wheel really is the way to do it. Cutting is fast and it is easy to get a straight line. Expect to use 3 or 4 wheels depending on how good of wheels you have. I cleaned everything up with a wire wheel fitted to my grinder now all that is left is to finish tacking it on. It is tacked on but I didn't take any pictures since it was dark already.
