Thanks for the pictures Doug. I appreciate the real world perspective. While theory is nice seeing practical applications in living color really helps and gives me hope that my project will turn out (half) as good.

Oh, and my feeling is also hurt because nobody bowed down and thanked me for my ambiguous post filled with information you didn't ask for lol.

Also, to answer your original question - you can use mild steel 2xwhatever for outriggers and utilize your MIG to tack the CM together and it won't hurt. The TIG process will use mild steel filler rod so it will be compatible for lack of better terms.