I have an old 80's model tracker pontoon trailer that is ridden with cancer to the point I'm afraid to trailer it with the boat on it. Its made of light wall tubing I'm going to rebuild it using 4" channel iron ( no place to hold water ).My question is the trailer is single axel and holds a 24'er if I add a second axel exactly where should it be placed? I'm thinking that the equelizer should be centered over the current axel is this correct? any feed back is appreciated