OK, I gots to throw my .02 in here. First off, you dont need stainless rod, second 70 series rod is not nickle, its low hydrogen, and its what you want to use, dont bother with the special rods for cast welding, they cost a fortune and if ya do it right are unnecessary. Heres where we get to the doublewide (trailerpark) engineering. For the preheat, use a small 6011 rod and low amps. Mark out where your weld will be, and burn a 6011 along that line, then grind it down smooth, like it was never there. Thatll give you a more uniform preheat than using a torch. Place your bracket, and weld with the 7018. Wait for a bit, a beer length should do it <IMG SRC="smilies/beer.gif" border="0"> , then run a second pass over it with the 6011, but dont touch the base metal. Thatll be your tempering bead, only weld on the first weld, keeps the heat in the fusion zone. put the assembly out in the bright noonday sun and allow to cool naturally, and your good to go. Might be a good idea to practice with an old center section before ya try this for real. As for the welds on the tubes, just weld away, youll be fine. Is it scientific? no. Will it work?? yes. kind of a mixture of several schools, lots of experience, and a bit of good ole doublewide engineering <IMG SRC="smilies/biggrin.gif" border="0">