I wish I had read this a couple months ago before I just did a bunch of MIG welding on my 55. Still learning after years of trying. It is never good enough, and many times I'm afraid to pull the trigger after spending hours to fit a piece. He made a good point on the weld-through primer too. I did set up my welding helmet for a fresh air supply, but I could have used much more ventilation which is hard to do when it's like a 100 below freaking zero. It's a great body work forum too.
http://autobodystore.com/new_page_11.shtml