The Phantom II is very roomy so I just ran my 4mm line down each side of the fuse then onto the injector tube on each side. I attached each injector tube to the fuse. I ran the tube thru the holes in the aft pipe support ring and then bent the tobe 90 degrees into the exhaust stream.

On the streight pipe setups I would lengthen the injector with more hard tube and pass it between the walls of the pipe to superheated the fluid.