Any advice on cutting square tube?

[performance]

To get the MOST out of the PP50, turn the plasma down to about 30 amps. Then get a tri square (also known as a speed square or Johnson). Hold it on the mark, allowing compensation for the torch tip and kerf and use it as a guide. Just drag it across the metal. Flip the tubing and cut the next side. I've done several thousand feet of tubing cuts this way. Its fast and accurate enough. The thing to watch for is that your cuts will match up once you get to the fourth side. Starting on the edge and dragging toward you is safe and effective. With a little practice it will become a seamless motion. The torch arc should start on the radius of the tube, so it won't create much if any blowback.